Mitsubishi Electric MELSERVO-J4 series, Instruction Manual

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340
11 OPTIONS AND PERIPHERAL EQUIPMENT
11.2 Regenerative options
Linear servo motor
■
Thrust and energy calculation
The following shows equations of the linear servo motor thrust and energy at the driving pattern above.
From the calculation results in 1) to 8), find the absolute value (Es) of the sum total of negative energies.
■
Losses of servo motor and servo amplifier in regenerative mode
For inverse efficiency and capacitor charging energy, refer to the following.

Page 339 Losses of servo motor and servo amplifier in regenerative mode
■ Regenerative energy calculation
Subtract the capacitor charging from the result of multiplying the sum total of regenerative energies by the inverse efficiency to
calculate the energy consumed by the regenerative resistor.
ER [J] =
η • E
s
- E
c
From the total of ER's whose subtraction results are positive and one-cycle period, the power consumption PR [W] of the
regenerative option can be calculated with the following equation.
PR [W] = total of positive ER's/one-cycle operation period (tf)
Select a regenerative option from the PR value. Regenerative option is not required when the energy consumption is equal to
or less than the built-in regenerative energy.
Section Thrust F of linear servo motor [N] Energy E [J]
1) F
1
= (M
1
+ M
2
) • V/t
psa1
+ F
t
E
1
= V/2 • F
1
• t
psa1
2) F
2
= F
1
E
2
= V • F
2
• t
1
3) F
3
= -(M
1
+ M
2
) • V/t
psd1
+ F
t
E
3
= V/2 • F
3
• t
psd1
4), 8) F
4
, F
8
= 0 E
4
, E
8
= 0 (No regeneration)
5) F
5
= (M
1
+ M
2
) • V/t
psa2
+ F
t
E
5
= V/2 • F
5
• t
psa2
6) F
6
= F
t
E
6
= V • F
6
• t
3
7) F
7
= -(M
1
+ M
2
) • V/t
psd2
+ F
t
E
7
= V/2 • F
7
• t
psd2
Linear servo motor
secondary-side (magnet)
Load
V
M
1
M
2
Linear servo motor
primary-side (coil)
Linear servo motor
F
t
2)
1)
V
3)
4)
Positive
direction
6)
5) 7)
Negative
direction
8)
Time
Feed speed
t
psa1
t
1
t
psd1
t
2
t
psa2
t
3
t
4
t
psd2