Delta Electronics VFD-EL manual VFD Series

Appendix B Accessories

100%

	T1	ED% = T1/T0x100(%)
Braking Time
		T0
Cycle Time

9.For safety reasons, install a thermal overload relay between brake unit and brake resistor. Together with the magnetic contactor (MC) in the mains supply circuit to the drive it offers protection in case of any malfunctioning. The purpose of installing the thermal overload relay is to protect the brake resistor against damage due to frequent brake or in case the brake unit is continuously on due to unusual high input voltage. Under these circumstances the thermal overload relay switches off the power to the drive. Never let the thermal overload relay switch off only the brake resistor as this will cause serious damage to the AC Motor Drive.

NFB

R/L1

S/L2

T/L3

O.L.

Thermal

Overload Relay or temperature switch

MC	R/L1	U/T1
	S/L2	V/T2		IM
	T/L3	W/T3		MOTOR	Thermal Overload
	VFD Series
				B1	Relay
MC		+(P)	+(P)		O.L.
		-(N)	-(N)				Brake
SA				Brake		BR	Resistor
Surge				Unit
Absorber				B2			Temperature

Switch

Note1: When using the AC drive with DC reactor, please refer to wiring diagram in the AC drive user manual for the wiring of terminal +(P) of Brake unit.

Note2: Do NOT wire terminal -(N) to the neutral point of power system.

Revision August 2008, 2ELE, V1.02 B-3