Mitsubishi Electric MELSERVO-J4 series Instruction Manual page 293

11. Options and peripheral devices
(2) Linear servo motor
(a) Thrust and energy calculation
Liner servo motor
secondary-side (magnet)
Liner servo motor
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.
(b) Losses of servo motor and servo amplifier in regenerative mode
For inverse efficiency and capacitor charging energy, refer to (1) (b) of this section.
(c) 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 • Es - Ec
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.
V
Load
M
1
F
t
M
2
Liner servo motor
primary-side (coil)
Section Thrust F of linear servo motor [N]
1) F = (M
1
2) F = F
2
3) F = -(M
3
4), 8) F F
4,
5) F = (M
5
6) F = F
6
7) F = -(M
7
Feed speed
2)
V
1) 3)
Positive
direction
4)
t t t
psa1 1 psd1
+ M ) • V/t + F
1 2 psa1 t
1
+ M ) • V/t + F
1 2 psd1 t
= 0
8
+ M ) • V/t + F
1 2 psa2 t
t
+ M ) • V/t + F
1 2 psd2 t
11 - 12
8)
Negative
direction
5) 7)
6)
t t t t t
2 psa2 3 psd2 4
Energy E [J]
E = V/2 • F • t
1 1 psa1
E = V • F • t
2 2 1
E = V/2 • F • t
3 3 psd1
E , E = 0 (No regeneration)
4 8
E = V/2 • F • t
5 5 psa2
E = V • F • t
6 6 3
E = V/2 • F • t
7 7 psd2
Time