Thermal Considerations, Power dissipation

Thermal Considerations

	Power dissipation		Operating without additional heatsink
	Power dissipation of a 55V amplifier		Attaching a heatsink
	Power dissipation of a 100V amplifier		Base plate thermal characteristics
	Power dissipation of a 200V amplifier (exc. 15A type)		Thermal Conclusions

Power dissipation

The power dissipation (P) of the VIO/PIC/FLU modules is given in the following formula:

P = K switching x V supply x I motor + K conduction x I ² motor

Power dissipation of a 55V amplifier

Power dissipation of a 100V amplifier

Power dissipation of a 200V amplifier (exc. 15A type)

Operating without additional heatsink

- is the temperature increase of the base plate due to the heat dissipation.

PDISSIPATION - is the power dissipated by the amplifier.

RTCA - is the Thermal resistance, in °C / Watt, between the base plate and the Ambient.

"t" - is the time, in minutes, the heat is dissipated.

- is the thermal time constant of the base plate.

TC - is the temperature of the amplifier's base plate.

When Tc reaches the temperature of Tc(max) the amplifier is disabled by the temperature protection.

Attaching a heatsink

	RTCH - is the thermal resistance between the base plate of the amplifier and the additional Heatsink.
	RTHA - is the thermal resistance between the additional Heatsink and the Ambient.

Note:
The RTCH depends on the attachment quality of the amplifier to the additional heatsink. The above figures are typical values.

Base plate thermal characteristics

	Copper based heatsink contributes to an excellent heat conduction.
	Each base plate is capable of dissipating (without an additional heatsink):
	- 10W (for PIC/FLU)
	- 7W (for VIO)

Thermal Conclusions

	The PIC/FLU base plate can dissipate approx. 40% of the heat generate when running at rated power.
	Output power higher than 40% of rated power requires additional heatsink.

	The VIO base plate can dissipate approx. 33% of the heat generate when running at rated power.
	Output power higher than 33% of rated power requires additional heatsink.