Power Supply Equipment Capacity And Generated Loss - Mitsubishi Electric Melservo-H Series Specifications And Instruction Manual

8. CHARACTERISTICS

8.2 Power supply equipment capacity and generated loss

(1) Power supply equipment capacity and generated loss
Table 8.1 indicates the generated loss and power supply capacity under rated load per combination of
the converter unit and servo amplifier. When the servo motors is run at less than the maximum speed,
the power supply equipment capacity is lower than the value in the table but the heat generated does
not change.
Since the servo motor requires 2 to 2.5 times greater instantaneous power for acceleration, use the
power supply which ensures that the voltage lies within the permissible voltage fluctuation at the
main circuit power supply terminals (L1, L2, L3) of the converter unit. The power supply equipment
capacity changes with the power supply impedance.
The actually generated heat falls within the ranges at rated torque and at zero torque according to the
frequencies of use during operation. When designing an enclosed control box, use the values in the
table, considering the worst operating conditions. The generated heat in Table 8.1 does not include
heat produced during regeneration.
Table 8.1 Power Supply Capacity and Generated Heat Per Servo Amplifier at Rated Output
Servo Amplifier Converter Unit
MR-H30K MH-HP30KA
Note: The heat generated by the servo amplifier is indicated in the left term within the parentheses,
and the heat generated by the converter unit in the right term.
(2) Heat dissipation area of enclosed control box
When setting the temperature inside the enclosed control box (hereafter referred to as the control box)
which will contain the converter unit and servo amplifier, factor in the allowance of about 5°C (41°F)
relative to the maximum operating environmental condition temperature of 55°C (131°F) so that it is a
maximum of 10°C (50°F) higher than the ambient temperature of 40°C (104°F). Use Expression (8.1)
to calculate the heat dissipation area of the control box.
P
......................................................................................................................................................(8.1)
A
K T
where, A
P
T
K
When calculating the heat dissipation area with Equation 8.1, assume that P is the sum of all losses
generated in the enclosure. Refer to Table 8.1 for heat generated by the servo amplifier. "A"
indicates the effective area for heat dissipation, but if the enclosure is directly installed on an
insulated wall, that extra amount must be added to the enclosure's surface area.
The required heat dissipation area will vary wit the conditions in the enclosure. If convection in the
enclosure is poor and heat builds up, effective heat dissipation will not be possible. Therefore,
arrangement of the equipment in the enclosure and the use of a fan should be considered.
Table 8.1 lists the enclosure dissipation area for each servo amplifier when the servo amplifier is
operated at the ambient temperature of 40°C (104°F) under rated load.
Power Supply
Capacity [kVA]
48
: Heat dissipation area [m
: Loss generated in the control box [W]
: Difference between internal and ambient temperatures [°C]
: Heat dissipation coefficient [5 to 6]
(Note)
Servo Amplifier-Generated Heart[W]
At rated torque At zero torque
1650
(1100 550) (30 30)
2 ]
8 - 2
Area Required for Heat Dissipation
2
[m ]
60
24.1
2
[ft ]
259.4