FANUC a Series AC SERVO MOTOR. Description Manual (GFZ-65142E/02)

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

4.1.2

Following the procedure described below, calculate the torque required

for acceleration:

Calculating the

Acceleration Torque

Calculating acceleration

torque : Procedure 1

Assuming that the motor shaft operates ideally in the acceleration/

deceleration mode determined by the NC, calculate the acceleration.

Multiply the acceleration by the entire inertia (motor inertia + load

inertia). The product is the acceleration torque. The equation is given

below.

A In linear

acceleration/deceleration

Speed

Torque

Command

Operation of

the motor

Time

Vm Speed

Speed variation

Acceleration required to

achieve the speed

Ta +^Vm

J_M

(1-e-ks@ta)

)^Vm

J_L

(1-e-ks@ta) B A

Vr + Vm

{1-

ta @ ks(1-e-ks@ta)^}

: Acceleration torque (kgf⋅cm)

Vm : Motor speed in rapid traverse (min^-1)

: Acceleration time (sec)

J_M : Motor inertia (kgf⋅cm⋅sec²)

J_L

: Load inertia (kgf⋅cm⋅sec²)

: Point from which the acceleration torque starts to de-

crease (difference from Vm) (min^-1)

: Servo position loop gain (sec^-1)

: Machine tool efficiency

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Example)

Try to perform linear acceleration/deceleration under the following

condition.

When α2/3000 is used, the load inertia is calculated as follows. First

select the α2/3000 and calculate its acceleration torque. J_M motor

inertia is 0.0061 (kgf⋅cm⋅s²), Vm is 3000 (min^-1), ta is 0.1 (s), ks is 30

(sec^-1), and J_L = 0.0247 (kgf⋅cm⋅s²).

3000

Ta +

0.0061

(1-e-30

^0.1)

0.1

)³⁰⁰⁰

0.0247

(1-e-30

^0.1) B 0.9

0.1

+ 100.1(kgf @ cm) + 9.81(Nm)

Torque (Nm)

12.1 (Nm)

2049 (min^-1)

Speed (min^-1)

Speed-torque characteristics of

α2/3000

α3/3000

The speed-torque characteristics of α2/3000 show that the acceleration

torque of 9.81 (Nm) is beyond the intermittent operating zone of α2/3000

(see the characteristic curve above and data sheet).

(The torque is

insufficient for α2/3000.)

If the operation specifications of the shaft (for instance, the acceleration

time) cannot be changed, a larger motor must be selected. Select an

α3/3000 (J_M is 0.02 (kgf⋅cm⋅s²)) and calculate the acceleration torque

again.

Ta = 123.7 (kg⋅cm) = 12.1 (Nm)

Vr = 2049 (min^-1)

In acceleration, an acceleration torque of 12.1 (Nm) is required at 2049

(min^-1). The speed-torque characteristic curve shown above shows that

the acceleration is possible with α3/3000.

As α2/3000 is changed to α3/3000, the size of the attachment flange is

increased from 90 mm x 90 mm to 130 mm x 130 mm. If the machine

tool does not allow a larger motor, the specifications must be changed.

For example, the acceleration time must lengthen.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

A When acceleration/

deceleration is not

Speed

Torque

controlled

Command

Operation of

the motor

Time

Vm Speed

Assume these equations.

Ta E^Vm

ta E

60A2p

taA(JM C^JL)

Calculating acceleration

To obtain T (torque) required by the motor shaft, add Tm (friction torque)

torque : Procedure 2

to Ta acceleration torque.

TETa CTm

T=12.1(Nm)+0.9(Nm)=13.0(Nm)

Calculating acceleration

Check that T obtained in Procedure 2 above is smaller than or equal to the

torque : Procedure 3

torque limit determined by the amplifier. Using the speed-torque

characteristic curve on the data sheet of the corresponding motor, check

that T obtained in Procedure 1 above is within the intermittent operating

zone at Vr.

As Vr is 2049 (min^-1) and T is 13.0 (Nm), the acceleration is possible with

the specified time constant (condition 2).

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

4.1.3

Calculating the

Root-mean-square

Value of the Torques

Calculating the

Generate an operation cycle which includes rapid traverse. Write the

frequency of positioning

time-speed graph and time-torque graph as shown below.

in rapid traverse

In a common cutting machine, the frequency of positioning in rapid

traverse will cause no problems. In a special machine tool which

frequently executes rapid traverse, however, the motor must be checked

to see whether it is overheated by the current required for acceleration or

deceleration.

Speed

Torque

Ta+Tf

Time

Ta-Tf

Time

t₁

t₂

t₁

t₃

t₁

t₂

t₁

t₃

From the time-torque graph, obtain the root-mean-square value of

torques applied to the motor during the single operation cycle. Check

whether the value is smaller than or equal to the rated torque (condition

3).

(Ta ) Tm)²t₁ ) Tm²t₂ ) (Ta-Tm)²t₁ ) To²t₃

Trms +

t_O

: Acceleration torque

Tm : Friction torque

: Torque when stopped

If Trms is smaller than or equal to the rated torque at stall (Ts), the motor

can be used.

(Set a value equal to 90% of the static rated torque, considering the total

thermal efficiency.)

Example)

When an α3/3000 (Ts = 31 (kgf⋅cm) = 3.0 (Nm)) is used under the

following conditions: Ta = 12.1 (Nm), Tm = To = 0.9 (Nm), t1 = 0.1

(s), t2 = 1.8 (s), t3 = 7.0 (s)

(12.1 ) 0.9)²

0.1 ) 0.9²

1.8 )

(12.1-0.9)²

0.1 ) 0.9²

Trms +

t_O

+ 20.2(Nm) t Ts

0.9 + 2.9

0.9 + 2.61(Nm)

The α3/3000 can be used for operation. (Condition 3)

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

Calculating the torque in

If the load conditions (cutting load, acceleration/deceleration conditions,

a cycle in which the load

etc.) vary widely in a single cycle, write a time-torque graph according

varies

to the operation cycle, as in above item. Obtain the root-mean-square

value of the torques and check that the value is smaller than or equal to

the rated torque (condition 4).

Torque

T₁

T₄

T_n

T₅

T₂

T₃

Time

t₁

t₂

t₃

t₄

t₅

t_n

t_o

T₁₂t₁ ) T₂₂t₂ ) T₃₂t₃ )AAA ) Tn2t_n

Trms +

t_o

to = t₁ + t₂ + … + Tn

4.1.4

Check that the time for which the table can be moved with the maximum

cutting torque, Tmc, (percentage duty cycle and ON time) is within a

Calculating the

desired range of cutting time. (Condition 5)

Percentage Duty Cycle

If Tmc (maximum load torque) applied to the motor shaft during cutting,

with the Maximum

which is obtained in Subsec. 4.1.1, is smaller than the product of rated

Cutting Torque

torque at stall of the motor (Tc) and α (thermal efficiency), the motor can

be used in continuous cutting. If Tmc is greater than the product (Tmc

> Tc _ α), follow the procedure below to calculate the percentage ratio of

time (t_ON) Tmc can be applied to the motor to total time (t) of a single

cutting cycle.

(α is assumed to be 0.9. Calculate the percentage

considering the specifications of the machine.)

Tmc t Tc a AAA Operation can be continued with the maximum

cutting torque.

(The percentage duty cycle with

the maximum cutting torque is 100%.)

Tmc u Tc a AAA Calculate the percentage duty cycle, according

to the following figure and expressions.

Example)

As calculated in Subsec. 4.1.1,

Tmc = 21.8 (kgf⋅cm) = 2.1 (Nm)

OS: Tc = 30 (kgf⋅cm) = 2.9 (Nm)

2.9 _ 0.9 = 2.6 (Nm) > 2.1 (Nm) = Tmc

No problems will occur in continuous cutting.

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Calculating the

percentage duty cycle

Torque

with the maximum

Maximum cutting torque (Tmc)

cutting torque

OFF

Time

t_ON

t _ON

: Time maximum cutting torque (Tmc) is applied

t _OFF

: Time no cutting torque is applied

: Maximum time of a single cutting cycle

Calculate the root-mean-square value of torques applied in a single

cutting cycle as described in Subsec 4.1.3. Specify t_ON and t_OFF so that

the value does not exceed the product of rated torque at stall of the motor

(Tc) and thermal efficiency (α). Then, calculate the percentage duty cycle

with the maximum cutting torque as shown below.

Percentage duty cycle with the

t_ON

100(%)

maximum cutting torque (Tmc)

Example)

Assume that Tmc is 4.0(Nm) (Tm = 0.9(Nm)).

4.0²

t_ON ) 0.9² t_OFF

t 2.6(Nm)

t_ON ) t_OFF

Therefore,

t_ON

t_OFF t

1.6

The ratio of non-cutting time to cutting time must be 1.6 or greater.

The percentage duty cycle is calculated as follows:

t_ON

100 + 38.5%

2.6t_ON

Finally, the α3/3000 that satisfies conditions 1 to 5 is selected.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

In the case where the machine moves in a linear direction and movement

4.2

is directly detected by linear scale such as inductosyn, magne-scale etc.,

PRECAUTIONS FOR

special considerations are necessary in comparison with the method

USING LINEAR

where feedback is produced by detecting the motor shaft rotation. This

SCALE

is because the machine movement now directly influences the

characteristics of the control system.

Machine system natural

frequency

Pulse coder Motor

Linear scale

Command

Position

Servo

control

amplifier

circuit

This method is shown in the figure above by block diagram. The response

of this control system is determined by the adjustment value (position

loop gain) of the position control circuit. In other words, the position loop

gain is determined by the specified response time of the control system.

In the diagram above, the section enclosed by the broken line is called the

velocity loop. Unless the response time of this section where position

signal is detected is sufficiently shorter than the response time determined

by the position loop gain, the system does not operate properly. In other

words, when a command signal is put into point A, response time of the

machine where position signals are detected must be sufficiently shorter

than the response time defined by the position loop gain.

When the response of the detector section is slow, the position loop gain

must be reduced to have the system operate normally, and as a result, the

response of the whole system is slow. The same problem is caused when

inertia is great (see section 4.1, item 1)).

The main causes for slow response are the mass of the machine and the

elastic deformation of the machine system. The larger the volume, and

the greater the elastic deformation, the slower the response becomes.

As an index for estimating the response of this machine system, the

natural frequency of the machine is used, and this is briefly calculated by

the following equation.

Wm +

Wm : Natural frequency

: Load inertia reflected to motor shaft (kgf⋅cm⋅s²)

Km : Rigidity of machine system (kgf⋅cm/rad)

=Torque necessary to elastically deform 1 rad at the motor

shaft when the machine table is clamped.

The above values can be obtained by calculating the elastic deformation

for each section of the driving system. If the value of this natural

frequency (Hz) is more than the value of position loop gain (see^-1), it

operates normally in most cases. That is to say, when setting 20 sec^-1 as

the value of position loop gain, natural frequency of machine system must

be more than 20 Hz. In this case, attention must be paid to the fact that

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

response becomes a problem for extremely small amounts of movement.

Consequently, the natural frequency should be calculated from the

rigidity at extremely small displacement such as less than 10 µm.

Stick slip

If machine movement causes a stick slip, the control system does not

operate normally. That is, it does not stop where it is supposed to, but a

phenomenon occurs where it goes beyond and then back within an

extremely small range (hunting). To avoid stick slip, the machine rigidity

should be increased, or friction characteristics of the sliding surface

should be improved. When the sliding surface friction characteristic is

as in the figure below, stick slip occurs easily.

Friction coefficient

Proper friction characteristic

Friction characteristic

which causes stick slip

Speed

Value of machine

When the machine is floated by static pressure, etc., there are cases where

overrun

the machine keeps on moving within the range of backlash although the

(Damping coefficient of

motor shaft has stopped. If this amount is large, hunting will also occur.

To avoid this, backlash should be reduced (especially the backlash of the

machine system)

last mass where position detector is mounted) and the appropriate

damping should be considered.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

Select a suitable motor according to the load condition, rapid traverse rate,

4.3

increment system, and so on. To aid in selecting the correct motor, fill out

MOTOR SELECTION

the ”servo motor selection data table” at the end of this section.

Fill in blanks of machine tool data items (No. 1, 2 and 3) of this table with

necessary data, and send this table to our representative.

The representative will fill in blanks of item No. 4 to 8 with suitable data

of motor and send this table back.

Details of each item in this selection data table are as described in Subsec.

4.3.1 and 4.3.2.

4.3.1

Blanks for Those Other

than Data

Kind of machine tool

Fill in this blank with a general name of machine tools, such as lathe,

milling machine, machining center, and others.

Type of machine tool

Fill in this blank with the type of machine tool decided by machine tool

builder.

CNC equipment

Fill in this blank with the name of CNC (15T, 16M, 0MC, etc.) employed.

Spindle motor output

Fill in this blank for reference when examining the servo motor output.

Names of axes

Fill in this blank with names of axes practically employed in CNC

command. If the number of axes exceeds 4 axes, enter them in the second

sheet.

Blanks of version

These blanks are left blank by the FANUC.

number, date, name, and

reference number.

4.3.2

Machine tool builders are requested to fill in data blanks No. 1, 2, 3. Fill

in No. 4 items and higher blanks with decided values or desired values,

Data

if any, from the viewpoints of specifications.

If these values are unknown or undecided, the representative will decide

these values according to the contents in item No. 1, 2, and 3. So leave

them blank. See the following for details of the contents of filling in.

No. 1 blank

Data in this blank are used for determining approximate values of motor

load conditions (inertia, torque). Fill in blanks of all items.

Enter the movement directions of driven parts such as table, tool post, etc.

A Axis movement direction

Write the angle from the horizontal level, if their movement directions are

slant (Example : Slant 60°)

Whether their movement directions are horizontal or vertical (or slant) is

necessary for calculating the regenerative energy. Fill in this blank

without fail.

Enter the weight of driven parts, such as table , tool post, etc. by the

A weight of driven parts

maximum value including the weight of workpiece, jig, and so on. Do

not include the weight of the counter balance in the next item in this item.

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

A Counter balance

Enter the weight of the counter balance in the vertical axis, if provided.

Write the force in case of hydraulic balance.

A Table support

Enter the type of table slide as to rolling, sliding, or static pressure type.

If a special slide way material like Turcite is used, note it.

A Feed screw

Enter the diameter, pitch, and axial length of the lead screw in order.

A Total gear ratio

Enter the gear ratio between the ball screw and the servo motor, gear ratio

between the final stage pinion and the servo motor in case of the rack

pinion drive, or gear ratio between the table and the motor in case of rotary

table.

No. 2 blank

Data in this blank serve as the basis for selecting the motor. Enter these

data correctly. For details of calculating methods of respective items,

refer to sec. 4.1 and 4.2.

A Movement per rotation of

Enter the movement of the machine tool when the motor rotates one turn.

motor

Example

A When the pitch of ball screw is 12 mm and the gear ratio is 2/3,

2/3 = 8 mm

A When the gear ratio is 1/72 in rotary table ;

360

1/72 = 5 deg

A Least input increment

Enter the least input increment of NC command. The standard value is

CNC

0.001 mm in Series 0, 15, 16, and 18 CNCs.

A Rapid traverse rate and

Enter the rapid traverse rate and cutting feedrate required for machine tool

cutting feedrate

specifications.

A Inertia

Enter a load inertia value reflected to the motor shaft. For details of this

calculation, see Subsec. 4.1.1.

It is not always necessary to enter this inertia value in detail.

Enter it as a 2-digit or 1-digit value. (Example : 0.2865³0.29 or 0.3)

Do not include any inertia of the motor proper in this value.

A Load torque

A Since the torque produced in low speed without cutting may be applied

even during the stop of motor, a sufficient allowance is necessary as

compared with the continuous rated torque of the motor. Suppress this

load torque to be lower than 70% of the rated torque.

A For the torque during rapid traverse, enter the torque during traveling

at rapid traverse steady-state speed.

Keep this value within the continuous rating. Do not include any

torque required for acceleration/deceleration in this item.

A For the cutting torque, enter the maximum value of the force being

applied during cutting by the force in the feed axis direction.

A For the maximum cutting torque, enter the torque value on the motor

shaft corresponding to the maximum value of the above cutting thrust.

Since the torque transfer efficiency may substantially deteriorate to a

large extent due to the reaction from the slide way, etc. produced by

the cutting thrust, obtain an accurate value by taking measured values

in similar machine tools and other data into due account.

A If the load torque values differ during lifting and lowering in the

vertical axis, enter both values.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

A Maximum cutting duty /

Enter the duty time and ON time with the maximum cutting torque in item

ON time

“Load torque” applied. These values mean as follows.

Torque

Maximum cutting torque (Tmc)

OFF

Time

: Time the maximum cutting torque (Tmc) is being applied.

OFF

: Time absent from the cutting torque

Duty

: t/T

100 (%)

On time = t (min)

A Rapid traverse

Enter the rapid traverse positioning frequency by the number of times per

positioning frequency

minute. This value is used to check if the motor is overheated or not by

a flowing current during acceleration / deceleration or to check the

regenerative capacity of the amplifier.

No. 3 blank

Data in this blank are necessary for examining the stability of the servo

system when the position detector is attached outside the motor. Enter

these data without fail when the servo system is constructed using a linear

scale.

A Separate type position

If the position detector is mounted outside the motor, enter the name of

detector

the detector. Enter the following items in the “remarks” column, if a

rotary detector such as resolver, pulse coder, or the like is used.

A Resolver

Move amount of machine tool per revolution of resolver

Number of wave lengths per revolution of resolver

A Pulse coder

Move amount per revolution of pulse coder

Number of pulses of pulse coder

A Rigidity of feed system

Enter the relation between the torque and the displacement when the

machine tool

torque is applied to the motor shaft, assuming that the final driven part like

the table has been fully locked. Fill in this value as a torque value required

for the angular displacement of 1 radian.

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Example)

If displacement of 5 deg. at 500 kgf⋅cm torque as a calculation results,

500

180

Rigidity +

+ 5730kgf @ cmńrad

If the relation between the displacement and the torque is nonlinear,

calculate the rigidity by the gradient in the vicinity of origin.

Torque

(Nm)

Rigidity +^T

e (Nmńrad)

Displacement (rad)

A Backlash amount

Enter the backlash amount between the motor and the final driven part like

table by converting it into the move amount of the table.

No. 4 blank

Motor specifications

A Motor model

Enter the model name of the motor employed and the specifications of the

Feedback (FB) type

built-in feedback unit by using symbols.

A Option, special

Enter special specifications, if any, in this blank.

specifications

No. 5 blank

The acceleration / deceleration time in this item is a commanded value.

It does not mean any actual completion time of positioning.

A Acceleration /

The acceleration/deceleration time is determined according to the load

deceleration time at

inertia, load torque, motor output torque, and working speed. For details

rapid traverse

of calculations, refer to Subsec. 4.1.2 and 4.1.3.

The acceleration/deceleration mode at rapid traverse is generally linear

acceleration/deceleration in FANUC’s CNC.

Speed

Time

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

A Acceleration/

The acceleration/deceleration at cutting feed is exponential acceleration

deceleration time at

/deceleration in general. This blank is filled in with its time constant

cutting feed

Speed

0.632Vm

Time

te : Time constant

No. 6 blank

A Input multiply ratio,

The NC set values required for moving the machine tool at the least input

command multiply ratio,

increment values are entered in these blanks.

and flexible feed gear

The relation among these values as illustrated below.

ratio

Command multiply ratio

Error

CMR

Flexible

feed gear

In the above figure, each ratio is set so that the units of the two inputs (a

and b) of the error register are the same. The pulse coder uses a flexible

feed gear as standard. So, CMR is normally set to 1. When other than

1 is to be set for CMR, contact FANUC for details.

For the flexible feed gear (F.FG), the ratio of the number of position pulses

required per motor shaft revolution to the number of feedback pulses is

set. The set value is obtained as follows:

Number of position pulses required

per motor shaft revolution

F.FG +

1,000,000

Note

For calculation, the number of feedback pulses for the α

pulse coder must always be set to

1,000,000.

The

maximum permissible value for both the numerator and

denominator is 32,767. So, the fraction should be reduced

to its lowest terms, after which the resultant numerator and

denominator should be set.

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Example)

Suppose that the NC uses increments of 1 m, the machine travel

distance per motor shaft revolution is 8 mm, and pulse coder A64 is

used.

8, 000

F.FG E

CMR E 1

1, 000, 000E

125,

Setting F.FG when 1 µ m detection is performed using the semi-closed

loop

Machine travel dis-

Number of required

tance per motor shaft

position pulses

F.FG value

revolution (mm/rev)

(pulses/rev)

10000

1/100

20000

2/100 or 1/50

30000

3/100

A Position loop gain

Fill in this blank with a value which is considered to be settable judging

it from the inertia value based on experiences.

Since this value is not always applicable due to rigidity, damping

constant, and other factors of the machine tool, it is usually determined

on the actual machine tool. If the position detector is mounted outside the

motor, this value is affected by the machine tool rigidity, backlash

amount, and friction torque value. Enter these values without fail.

No. 7 blank

The coasting distance of the machine tool at the machine tool stroke end

is entered in this blank. The stroke end is usually limited in 2 steps

consisting of the deceleration stop in the first step and dynamic brake stop

in the second step.

The position display accurately coincides with the stop position of the

machine tool when the first step limit switch is depressed. However, this

position is lost when the second step limit switch is depressed. Mount this

second limit switch without fail for preventing the machine tool from

being damaged, because it is only one means of stopping the machine

tool, if the machine tool should run away due to a control failure.

A Deceleration stop

Enter the coasting distance when the machine tool is decelerated and

distance

stopped at the stroke end.

Vm : Rapid traverse rate, mm/min or deg /min

l₁

: Coasting distance due to delay time t₁ of receiver

l₂

: Coasting distance due to deceleration time t₂

l₃

: Servo deflection amount

t₁

: Usually about 0.02 seconds

t₂

Coasting distance E^Vm

60A(t1 C

k_s

k_s : Position loop gain (sec^-1)

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

A Dynamic brake stop

This is coasting distance when the machine tool is stopped by dynamic

distance

braking with both ends of the motor power line shorted, if the machine

tool is in trouble.

Vm : Rapid traverse rate, mm/min or deg /min

l₁

: Coasting distance due to delay time t₁ of receiver

l₂

: Coasting distance due to deceleration time t₂ of magnetic con-

tactor (MCC)

l₃

: Coasting distance by dynamic braking after magnetic contactor

has been operated

(t₁+t₂) is usually about 0.05 seconds.

Coasting distance(mm or deg)

E^Vm

t₂) C (J_m C J₁) A (ANo C BNo³) A L

60A(t1 C

Jm : Motor inertia (kg·cm·s²)

: Load inertia (kg·cm·s²)

No : Motor speed at rapid traverse (rpm)

: Machine movement on one-rotation of motor (mm or deg)

NoL=Vm

A and B are constants that vary with the model of the motor being used.

The values for each model are listed under ”Coefficients for Calculating

the Dynamic Brake Stopping Distance.”

No. 8 blank

Servo amplifier specification

A Type of amplifier

Designate AC servo.

A Transformer

Fill the transformer specification.

A Specifications

Enter the servo amplifier module specifications.

Coefficients for

calculating the dynamic

Model

Jm (kgf⋅cm⋅s²)

brake stopping distance

α series

α0.5/3000

8.1A10^-2

5.9A10^-8

0.00018

α1/3000

5.9A10^-2

1.3A10^-8

0.0037

α2/2000

1.9A10^-2

5.3A10^-9

0.0061

α2/3000

2.2A10^-2

4.6A10^-9

0.0061

α3/3000

1.4A10^-2

7.3A10^-9

0.014

α6/2000

5.5A10^-3

4.4A10^-9

0.027

α6/3000

1.1A10^-2

2.1A10^-9

0.027

α12/2000

3.0A10^-3

6.8A10^-9

0.064

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Model

Jm (kgf⋅cm⋅s²)

α12/3000

6.7

10^-3

3.1

10^-9

0.064

α22/1500

1.5

10^-3

3.3

10^-9

0.12

α22/2000

2.8

10^-3

1.8

10^-9

0.12

α22/3000

4.2

10^-3

1.2

10^-9

0.12

α30/1200

8.6

10^-4

2.5

10^-9

0.17

α30/2000

1.1

10^-3

2.0

10^-9

0.17

α30/3000

2.5

10^-3

8.6

10^-10

0.17

α40/2000

1.1

10^-3

1.1

10^-9

0.23

α65/2000

1.7

10^-3

4.2

10^-10

0.19

α100/2000

1.3

10^-3

2.4

10^-10

0.27

α150/2000

1.0

10^-3

1.7

10^-10

0.35

α(HV) series

α3/3000HV

3.4

10^-2

3.0

10^-9

0.014

α6/3000HV

1.3

10^-2

1.8

10^-9

0.027

α12/3000HV

1.4

10^-2

1.5

10^-9

0.064

α22/3000HV

7.8

10^-3

6.4

10^-10

0.12

α30/3000HV

4.3

10^-3

5.0

10^-10

0.17

αC series

αC3/2000

8.3

10^-3

1.3

10^-8

0.014

αC6/2000

2.7

10^-3

8.8

10^-9

0.027

αC12/2000

1.4

10^-3

1.5

10^-8

0.064

αC22/1500

1.5

10^-3

3.3

10^-9

0.12

αM series

αM3/3000

2.0

10^-2

7.1

10^-9

0.008

αM6/3000

9.7

10^-3

2.7

10^-9

0.014

αM9/3000

5.5

10^-3

1.0

10^-9

0.026

αL series

αL3/3000

2.3

10^-2

3.0

10^-8

0.0025

αL6/3000

1.4

10^-2

1.1

10^-8

0.0050

αL9/3000

1.1

10^-2

1.9

10^-9

0.010

αL25/3000

3.6

10^-3

1.6

10^-9

0.055

αL50/2000

1.7

10^-3

1.1

10^-9

0.10

The values of A and B are calculated by assuming that the resistance of

the power line is 0.05 Ω per phase. The values will vary slightly according

to the resistance value of the power line.

Coefficient will vary depending on the servo amplifiers. The machine

may stop by a less distance movement by the coefficient.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

MTB

AC servo motor selection data table

Machine

Kind

Type

NC, spindle motor

NC ; FANUC

(

)

Spindle motor

Axis

No.

Item

Axis movement direction (horizontal, vertical rotation)

Weight of moving component parts

(including workpiece, etc.)

kgf

Counter balance

kgf

Table support (sliding, rolling, static pressure)

Diameter

Feed screw

Pitch

Axial length

Total gear ratio

Movement of machine tool per revolution of motor

Least input increment of NC

Rapid traverse feedrate

mm/min

Cutting traverse feedrate

mm/min

Inertia

kgf⋅cm⋅sec²

Low feed without cutting

kgf⋅cm

Rapid traverse

kgf⋅cm

Load torque

Cutting thrust

Maximum cutting torque

kgf⋅cm

Maximum cutting duty/ON time

%/min

Rapid traverse positioning frequency

times/min

Separate type position detector

Feed system machine tool rigidity

kgf⋅cm/rad

Backlash amount

Motor type

FB type

Number of rotation at rapid traverse

rpm

Option / Special specifications

Acceleration/deceleration time at rapid traverse

msec

Acceleration/deceleration time at cutting feed

msec

Command multiply ratio

CMR

Detection multiply ratio

DMR

Flexible feed gear

FFG

Position loop gain

sec^-1

Deceleration stop distance

Dynamic brake stop distance

Amplifier type

Transformer

Specifications

Amplifier

Version

Date

Name

Remarks

FANUC LTD

A. Ar - 1870 -

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

MTB

Servo motor selection data table (models for positioning)

Machine

Model

NC model

NC ; FANUC

Name

Axis name

Item

Specifications of moving object

Direction of movement (horizontal, vertical, rotation)

Weight of the moving object (including the workpiece)

kgf

Counterbalance

kgf

Table support (sliding contact, rolling contact, static pressure)

(*)

Feed mechanism (Select one of the following and enter the corresponding data.)

1 Ball screw: Diameter _ pitch _ length

2 Rack and pinion: Diameter of pinion (traveling distance of the machine tool per

revolution of the pinion: mm)

3 Others

Mechanical specifications

Traveling distance of the machine tool per revolution of the motor

Total gear reduction ratio

Inertia (Note ”before deceleration” or ”applied to the motor shaft.”)

kgf⋅cm⋅sec²

Least input increment of NC (resolution)

Maximum rapid traverse feedrate

mm/min

Motor speed in rapid traverse

rpm

Acceleration/deceleration time in rapid traverse

msec

Distance of positioning in rapid traverse

Frequency of positioning in rapid traverse

times/min

In the remarks section, note the operation cycle (speed pattern) if it is determined.

Low feed without cutting

kgf⋅cm

Load torque

Rapid traverse

kgf⋅cm

Backlash

Fill in these blanks when an separate type position detector is used.(**)

Type of separate type position detector (detection unit, number of pulses, etc.)

Gear diameter and reduction ratio when a rotary encoder is used

Motor specifications

Motor type (desired size and output, if any)

FB type (when an absolute position detector is required)

Option (when a brake, non-standard shaft, etc. is required)

FANUC will fill in these blanks.

Command multiplier

CMR

Detection multiplier

DMR

Flexible feed gear

FFG

Position loop gain

sec^-1

Deceleration stop distance

Dynamic brake stop distance

Specifications of amplifier

Specifications of regenerative discharge unit

Specifications of transformer

(*) Note the friction coefficient of the sliding surface if it is determined.

(**) A separate type position detector is required when:

Note

-The positions of the motor and machine may be mechanically displaced, for example, by slippage of a

driving tire or an elongated driving chain.

Version

Date

Name

Remarks

FANUC LTD

A. Ar - 1870 -

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

Performance of each motor model is represented by characteristic curves

4.4

and data sheet shown below.

CHARACTERISTIC

CURVE AND DATA

SHEET

The typical characteristic curves consist of the following.

4.4.1

Performance Curves

Speed-torque

These are known as operating curves and describe the relationship

characteristics

between the output torque and speed of the motor. The motor can be

operated continuously at any combination of speed and torque within the

prescribed continuous operating zone. Outside of this zone, the motor

must be operated on an intermittent basis using the duty cycle curves. The

limit of continuous operating zone is determined under the following

conditions. And this zone may be limited by the thermal protection of

mounted precision instrument. (pulse coder)

A The ambient temperature for the motor is 20°C.

A The drive current of the motor is pure sine wave.

The limit of intermittent operating zone is determined by input voltage to

the motor.

Actual operation is limited by the current limit of servo unit.

Due to the negative temperature coefficient of the magnetic material,

continuous operating zone must be derated at the rate of 0.19% per degree

centigrade rise of magnets. (i.e. for ambient temperature above 20° derate

0.19% for each degree over)

Overload duty

These curves are known as duty cycle curves and provided very important

characteristic

information on how to determine the ”ON” time for intermittent overload

torque without overheating the motor. The curves shown in the following

figures are ones determined by the limit of the temperature of the motors.

When the motor is driven by some driving circuit having thermal protect

devices such as thermal relay or fuse, the ”ON” time may be limited by

the characteristics of those elements.

4.4.2

The data sheet gives the values of motor parameters relating to the

performance.

Data Sheet

The values of parameters are those under the following conditions.

A The ambient temperature for the motor is 20°C.

A The drive current of the motor is pure sine wave.

Important parameters on the data sheet are defined as follows :

Continuous RMS current at stall TENV : Is (Arms)

Motor can be operated at this RMS current continuously at stall (or low

speed) with TENV (Totally Enclosed Non Ventilation).

4. SELECTING A MOTOR

DESCRIPTIONS FOR THE α series

B-65142E/02

Torque constant : Kt (kgf⋅cm/Arms)

This is known as torque sensitivity and represents the torque

developed per ampere of phase current. This value can usually be

obtained by measuring the torque developed by rated current. The

torque constant is a function of the total flux and the total number of

conductors in the armature.

The back EMF constant and the torque constant are inter-related as

follows :

Kt(kgf @ cmńArms) + 30.6Kv(Volt @ sec ńrad)

Thus if Kv is reduced due to demagnetization of the magnetic field,

Kt is also reduced in the same proportion.

Back EMF (electromotive force) constant: Kv (volt·sec/rad)

The back EMF constant is the indication of the permanent magnet field

strength. It is the value of the generated voltage at a specified speed

when magnetic field is rotated mechanically, and is the function of

total number of conductors in the armature and total flux of the field.

The back EMF constant has the dimensions of volt-second per radian

or volts per rpm. The relationship can be given as :

Volt @ sec

+^Volt

9.55

rpm

rad

Back EMF constant is indicated as the RMS voltage per phase, so

multiply

to get actual terminal voltage.

Mechanical time constant : tm (sec)

This is a function of the initial rate of rise in velocity when a step

voltage is applied. It is calculated from the following relationship.

Jm @ Ra

tm +

Kt @ Kv

Jm : Rotor inertia (kgf⋅cm⋅s²)

Ra ; Resistance of the armature

Thermal time constant : t_t (min)

This is a function of the initial rate of rise of winding temperature at

rated current. It is defined as the time required to attain 63.2 percent

of the final temperature rise.

Static friction : Tf (kg⋅cm)

This is the no-load torque required just to rotate the rotor.

Max. current before demagnetization : Im (A)

This value of current is the instantaneous (peak) current which can be

applied to the motor without demagnetizing the permanent magnet

field. The magnet can be demagnetized even on only one pulse of high

current. Care should therefore be taken to limit peak currents to the

stated value. Repeated pulses at rated peak or less will not affect

demagnetization.

B-65142E/02

DESCRIPTIONS FOR THE α series

4. SELECTING A MOTOR

4.4.3

Servo motors can be operated in the range exceeding continuous rated

torque depending on thermal time constant. Duty characteristics shows

How to Use Duty Cycle

the Duty (%) and the ”ON” time in which motor can be operated under

Curves

the given overload conditions. Calculation procedure is as follows.

Calculate Torque percent by formula (b) below.

Motor can be operated at any point on and inside the curve

corresponding to the given over load conditions obtained form 1.

Calculate t_F by formula (a)

100

t_F + t_R a (

(a)

Duty percent-1)

Load torque

(b)

TMD +

Continuous rated torque

t_F

“OFF” time

t_R

“ON” time

The values of t_R and t_F obtained form the above mentioned procedure

shows the ones limited by motor thermal conditions. Other circuit

protectors such a thermal relay or fuse also limit the operating zone of

the motor. To determine t_R and t_F for actual use, characteristics of

those protectors must be considered.

In the case of digital servo, the software protection is available to

protect against a shorter time overload. This also limits the motor

operating conditions.

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

B-65142E/02

DESCRIPTIONS FOR THE α series

STANDARD

This chapter describes the conditions the following FANUC α, α(HV),

5.1

αC, αM, and αL series AC servo motors must clear before they can be

APPLICABLE

approved for the IEC34 standard.

MOTORS

5.1.1

From the FANUC α, αC, αM, and αL series AC servo motors listed

below, select the motors that meet any combination in “Motor Types and

200 VAC Input Types

Specifications” (sections II.2, IV.2, V.2, and VI.2) and either of the

following conditions: Designated as #Txxx or #Uxxx (where xxx is any

code) at the end of their specification code indicated on the nameplates,

or manufactured in March 1995 or later. The selected motors will meet

the IEC34 standard if they are used under the conditions described in this

chapter.

α series

α C series

Model name

Motor specification number

Mode name

Motor specification number

α0.5/3000

A06B-0113-Bxxx

αC3/2000

A06B-0121-Bxxx

α1/3000

A06B-0371-Bxxx

αC6/2000

A06B-0126-Bxxx

α2/2000

A06B-0372-Bxxx

αC12/2000

A06B-0141-Bxxx

α2/3000

A06B-0373-Bxxx

αC22/1500

A06B-0145-Bxxx

α3/3000

A06B-0123-Bxxx

α M series

α6/2000

A06B-0127-Bxxx

Model name

Motor specification number

α6/3000

A06B-0128-Bxxx

αM3/3000

A06B-0161-Bxxx

α12/2000

A06B-0142-Bxxx

αM6/3000

A06B-0162-Bxxx

α12/3000

A06B-0143-Bxxx

αM9/3000

A06B-0163-Bxxx

α22/1500

A06B-0146-Bxxx

α L series

α22/2000

A06B-0147-Bxxx

Model name

Motor specification number

α22/3000

A06B-0148-Bxxx

αL3/3000

A06B-0561-Bxxx

α30/1200

A06B-0151-Bxxx

αL6/3000

A06B-0562-Bxxx

α30/2000

A06B-0152-Bxxx

αL9/3000

A06B-0564-Bxxx

α30/3000

A06B-0153-Bxxx

αL25/3000

A06B-0571-Bxxx

α40/2000

A06B-0157-Bxxx

αL50/3000

A06B-0572-Bxxx

α40/2000

A06B-0158-Bxxx

Motor with fan

α65/2000

A06B-0331-Bxxx

α100/2000

A06B-0332-Bxxx

α150/2000

A06B-0333-Bxxx

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

STANDARD

DESCRIPTIONS FOR THE α series

B-65142E/02

5.1.2

From the FANUC α (HV) series AC servo motors listed below, select the

motors that meet any combination in III.2

“Motor Types and

400 VAC Input Types

Specifications” (described later). The selected motors will meet the

IEC34 standard if they are used under the conditions described in this

chapter.

(HV) series

Model name

Motor specification number

Model name

Motor specification number

α3/3000HV

A06B-0171-Bxxx

α12/3000HV

A06B-0176-Bxxx

α6/3000HV

A06B-0172-Bxxx

α22/3000HV

A06B-0177-Bxxx

α30/3000HV

A06B-0178-Bxxx

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

STANDARD

DESCRIPTIONS FOR THE α series

B-65142E/02

5.3

POWER CABLE

CONNECTORS

The connector kit or cable assembly specified below must be used to

5.3.1

connect a power cable to the model α 0.5. This connector is not

Model A 0.5

waterproof.

D Connector kit

Housing: 3-178129-6 [AMP Japan specification]

A06B-6050-K119 [FANUC specification]

(This specification includes the contacts.)

Contact: 1-175217-2 [AMP Japan specification]

- The contacts of the α 0.5 connector are one-piece crimp type. The

size of the applicable wire is AWG#20, and the outside diameter of

the insulation is 1.7 to 2.6 mm.

The following dedicated tools are required to mount and remove the

contacts. They should be prepared separately from the connector kit.

Crimping tool specification:

914595-3 [AMP Japan]

A97L-0200-0979 M [FANUC]

Extractor specification:

914677-1 [AMP Japan]

A97L-0200-0980/D3 [FANUC]

The following FANUC power cables use the wires that meet the VDE.

D Cable assembly (14 m as standard)

Model with no brake:

A06B-6050-K822 [FANUC specification]

Model with a built-in brake:

A06B-6050-K823 [FANUC specification]

5.3.2

Section 8.2.3 of IEC204-1 (EN60204-1), which must be met to acquire

CE marking approval, stipulates that all exposed live conductors of

Models A1 and A2

electric equipment and machines be connected to a protection link circuit.

If the connector portion of a motor is exposed to the outside, its metal

portion should be covered with a non-moving insulation, or the metal

shell should be connected to a protection link circuit using the following

connector kit.

D Connector kit: A06B-6050-K121 [FANUC specification]

- The contacts of the α1 and α2 connectors are one-piece crimp type.

The sizes of the applicable wires are AWG#18 and AWG#16

respectively, and the outside diameters of the insulations are 1.8 to

2.8 mm (for #18) and 2.2 to 2.8 mm (for #16).

The following dedicated tools are required to insert and remove the

contacts. They should be prepared separately from the connector kit.

Crimping tool specification:

914596-3 (AMP Japan)

A97L-0200-0979/L [FANUC]

Extractor specification:

914677-1 (AMP Japan)

A97L-0200-0980/D3 [FANUC]

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

B-65142E/02

DESCRIPTIONS FOR THE α series

STANDARD

- Cables with an external size of 9.9 to 10.9 mm² should be used to

provide a sufficient waterproof performance related to cable

clamps.

The number of cable conductors is 1 greater than the conventional

U/V/W/G/(B1)/(B2) to provide for the connector shell protection

link circuit, that is 5 or 7 conductors.

The following FANUC power cables use the wires that meet the VDE.

D Cable assembly (14 m as standard)

Model with no brake: A06B-6050-K824 [FANUC specification]

Model with a built-in brake:

A06B-6050-K825 [FANUC specification]

- The motor grounding wire (at terminal 4) and connector shell

grounding wire should be bundled with one crimping terminal and

connected to the grounding terminal of the amplifier. The

grounding lines must be indicated in yellow/green.

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

STANDARD

DESCRIPTIONS FOR THE α series

B-65142E/02

5.3.3

The motor power cable and brake fan unit must be connected using the

connectors and cable clamps specified below.

Models A3 and Higher

Motor

Plug connector maker

Cable clamp

model

specification

name

[FANUC specification]

and connector

maker name

α3/3000,

Straight

H/MS3106A18-10S-D-T (10)

H/MS3057-10A (10)

α6/2000,

type

[A63L-0001-0648/61810SH]

[A63L-0001-0592/10AK]

α6/3000,

α3/3000HV,

Hirose Electric

α6/3000HV,

αC3/2000,

αC6/2000,

αM3/ 3000,

L-shape

H/MS3108B18-10S-D-T (10)

αM6/3000,

type

[A63L-0001-0648/81810SH]

αM9/3000

αL3/3000,

αL6/ 3000,

αL9/3000

α12/2000,

Straight

JL04V-6A22-22SE-EB

JL04-2022CK-(14)

α12/3000,

type

[A63L-0001-0648/62222SJ]

[A63L-0001-0653/12A]

α12/3000HV,

Japan Aviation

α22/3000HV,

Electronics Industry

α30/3000HV,

α22/1500,

L-shape

JL04V-8A22-22SE-EB

α22/2000,

type

[A63L-0001-0648/82222SJ]

α30/1200,

αC12/2000,

αC22/1500

α22/3000,

Straight

JL04V-6A24-10SE (G)-EB

JL04-2428CK-(17)

α30/2000,

type

[A63L-0001-0648/62410SJ]

[A63L-0001-0653/16A]

α30/3000,

Japan Aviation

α40/2000,

Electronics Industry

α40/2000

L-shape

JL04V-8A24-10SE (G)-EB

(with fan)

type

[A63L-0001-0648/82410SJ]

αL25/3000,

αL50/2000

Brake and

Straight

JL04V-6A10SL-3SE-EB

JL04-1012CK-(05)

fan unit

type

[A63L-0001-0648/610SL3SJ]

[A63L-0001-0653/04A]

connection

L-shape

JL04V-8A10SL-3SE-EB

Japan Aviation

Electronics Industry

type

[A63L-0001-0648/810SL3SJ]

A Also see Section 8.

A The power cable for the α22/3000, α30/2000, α30/3000, α40/2000,

αL25/3000, and αL50/2000 has 7 conductors. Its grounding wire (one

conductor) must have a cross section not less than that for the U, V, or

W line (two conductors). For the grounding wire for the other

connectors, its cross section must not be less than that for the U, V, or

W line.

A If a cable or conduit hose seal adapter is used, consult an appropriate

connector maker.

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

B-65142E/02

DESCRIPTIONS FOR THE α series

STANDARD

The following specifications are approved for the IEC34 standard.

5.4

APPROVED

SPECIFICATIONS

5.4.1

The allowable maximum speeds of motors are as listed below.

Motor Speed (IEC34-1)

Motor model

Rated-output

Allowable maximum

speed [1/min]

α1/3000,

α2/3000,

3000

α3/3000,

α6/3000,

α12/3000,

α22/3000,

α30/3000,

α3/3000HV,

α6/3000HV,

α12/3000HV,

α22/3000HV,

α30/3000HV

αM3/3000,

αM6/3000,

αM9/3000,

αL3/3000,

αL6/3000,

αL9/3000

αL25/3000

α2/2000,

α6/2000,

2000

2500

α12/2000,

α22/2000,

α30/2000,

α40/2000,

αC3/2000,

αC6/2000,

αC12/2000,

αL50/2000

α22/1500,

αC22/1500

1500

2000

α30/1200

1200

1500

α65/2000,

α100/2000,

α150/2000

2000

Motors must not be used at a speed higher than the allowable maximum

speed. Motors cannot be used continuously at the allowable maximum

speed. The output is not specified for the allowable maximum speed. The

allowable maximum speed applies only to motors. Separate limits are

laid on the drive units.

The rated output is guaranteed as continuous output only for the

5.4.2

rated-output speed. At a speed other than the rate-output speed, the

Output (IEC34-1)

output is specified in terms of a continuous operation torque. The output

in an intermittent operation range is not specified. The approved output

of each model is as listed in II to VI.3,

“Specifications and

Characteristics” (described later) for the α, α(HV), αC, αM, and αL

series.

5.4.3

The protection types are as listed below.

Protection Type

Motor model

Approval conditions

(IEC34-5)

α0.5/3000

Applies only to the motor section;

for connectors, IP00 applies.

α65/2000, α100/2000,

Only when a conduit meeting

α150/2000

IP55 is used.

Models other than those listed

Only when a specified connector

above.

is used.

5. CONDITIONS FOR APPROVAL

RELATED TO THE IEC34

STANDARD

DESCRIPTIONS FOR THE α series

B-65142E/02

IP5x: Dustproof machines

A dust-proof machine shall be protected from dust to an extent that

dust does not impede the normal operation of the motor if the motor

is not protected from dust completely.

IPx5: Sprinkle-proof machines

A sprinkle-proof machine shall not suffer inadvertent influence when

they are exposed to water sprinkled from nozzles at any angle to the

machine.

The conditions of the IPx5 type test are as follows:

Nozzle inside diameter:

6.3 mm

Amount of sprinkled water:

12.5 liters/minute

Water pressure at the nozzle:

30 kPa

Sprinkle time per a surface of 1 m²:

1 minute

Minimum required time:

3 minutes

Distance between the nozzle and machine: Approximately 3 m

Note

IPx5 evaluates machines for waterproofness in a

short-term test as described above, allowing chances that

the machines may get dry after the test. If a machine is

exposed to liquids other than water or so continuously to

water that it cannot get dry, it may suffer inadvertent

influence even if the degree of exposure is low.

The motor cooling methods are as listed below.

5.4.4

Cooling Method

Motor model

IC code

Method

(ICE34-6)

α40/2000 with fan

IC 416

Fully closed; cooled by an external in-

dependent fan

Other models

IC 410

Fully closed; cooled by a natural air flow

5.4.5

The motors can be mounted by the following methods.

Mounting Method

IMB5: Flange mounting with the shaft facing sideways (from the rear)

(IEC34-7)

IMV1: Flange mounting with the shaft facing upward (from the rear)

IMV3: Flange mounting with the shaft facing downward (from the rear)

The heat protection type is as listed below:

5.4.6

T P 2 1 1

Heat Protection

1: Temperature rise limit category 1 for heat protection

(IEC34-11)

1: Stop only at stage 1 (no warning)

2: Protection for gradual and abrupt overload

FANUC a Series AC SERVO MOTOR. Description Manual (GFZ-65142E/02) - page 2