Parker Hannifin HD130 Operation of the Drive Protection Systems, Overload Protection, Supply

HD65 & HD130 STEPPER DRIVES USER GUIDE 17

Operation of the Drive Protection Systems

There are three basic protection systems built into the drive, and these guard against damage caused by overloads, power supply faults and excess temperature. Operation of any of these protection circuits will de-energise the drive, and the reason for shutdown is indicated by an LED on the front of the drive. Provided the cause of the fault has been removed the drive may be re-energised by taking control terminal 7 to 0v or by temporarily removing power. Figure 7 is a simplified diagram of the protection circuitry.

Overload
Protection
	An overload condition may be brought about by incorrect motor
	connection, short circuits across the motor terminals or any other
	condition causing excess current to flow. It may also arise if a very
	low inductance motor is desynchronised during deceleration. In any
	of these circumstances the overcurrent comparator will set the fault
	latch, turning on the appropriate LED and giving a fault output signal.
Supply	Should the high-voltage supply rise excessively, or any of the logic
Failure	supply rails fall outside preset limits, the supply protection circuit
Protection	comes into operation. It functions by using a comparator to compare
	each of the supply rails with fixed reference levels. If the preset
	limits are exceeded, the fault latch is set and the supply failure LED
	is illuminated. Note that an excessive rise in the high-voltage supply
	may result from failure of the power dump fuse FS2.

Over- temperature Protection

This mode of shutdown occurs if the heatsink temperature reaches 85°C, which will generally be the result of inadequate cooling. The heatsink temperature is monitored by a thermal sensor mounted on the drive pcb. The output from the sensor sets the fault latch directly, and illuminates the Overtemperature LED. It will be necessary to allow time for the drive to cool down before it can be reset.