10. CHARACTERISTICS
10 - 3
10.2 Power supply capacity and generated loss
(1) Amount of heat generated by the driver
Table 10.1 indicates drivers' power supply capacities and losses generated under rated load. For
thermal design of an enclosed type cabinet, use the values in the table in consideration for the worst
operating conditions. The actual amount of generated heat will be intermediate between values at
rated torque and servo-off according to the duty used during operation. When the servo motor is run
at less than the rated speed, the power supply capacity will be smaller than the value in the table, but
the driver's generated heat will not change.
Table 10.1 Power supply capacity and generated loss per servo motor at rated output
(Note 1)
Power supply
capacity
[kVA]
(Note 2) Driver-generated heat
[W]
Area required for
heat dissipation
[m
2
]
Note that the power supply capacity will vary according to the power supply impedance.
Heat generated during regeneration is not included in the driver-generated heat.
(2) Heat dissipation area for an enclosed type cabinet
The enclosed type cabinet (hereafter called the cabinet) which will contain the driver should be
designed to ensure that its temperature rise is within +10 °C at the ambient temperature of 40 °C.
(With an approximately 5 °C safety margin, the system should operate within a maximum 55 °C
limit.) The necessary cabinet heat dissipation area can be calculated by equation 10.1.
A =
·················································································································· (10.1)
A: Heat dissipation area [m
2
]
P: Loss generated in the cabinet [W]
ΔT: Difference between internal and ambient temperatures [°C]
K: Heat dissipation coefficient [5 to 6]