Delta Electronics VFD-G Time, Over-current Stall Prevention during Acceleration, Unit, Settings

Chapter 4 Parameters

Group 6: Protection Function Parameters

06 - 00 Over-voltage Stall Prevention

Factory Setting: 780.0

Settings 660.0V~820.0VDC 00: Disabled

This parameter selects the voltage level for the Over-Voltage Stall Prevention function. During decelerations, the DC bus voltage may exceed its maximum allowable value due to motor regeneration. When this function is enabled, the AC drive will stop decelerating and maintain a constant output frequency. The AC drive will only resume deceleration when the voltage drops below the preset value.

With moderate inertial loads, the over-voltage stall prevention will not occur and the deceleration time should be equal to Pr.1-10. With high inertial loads, the AC drive will automatically extend the deceleration time due to the step function shown below. If the deceleration time is critical for the application, then dynamic braking resistors should be used.

		Output frequency	Deceleration characteristic
			when Over-voltage stall
			prevention enabled
				Frequency held
					Time
			Deceleration Time
06 - 01	Over-current Stall Prevention during Acceleration						Unit: 1
	Settings	20~250%				Factory Setting: 150%

This parameter selects the percentage of allowable over-current during acceleration before the stall prevention is enabled.

During acceleration, the AC drive output current may increase abruptly and exceed the value specified by Pr.06-01 due to rapid acceleration or excessive load on the motor. When this function is enabled, the AC drive will stop accelerating and maintain a constant output frequency. The AC drive will only resume acceleration when the current drops below the value set in Pr.06-01 (please see the graph below).

4-52 Revision July 2008, EG03, SW V1.06