Siemens 125-3208 operating instructions Electronic Bypass Option Overview, General Description

SED2 VFD Electronic Bypass Option Operating Instructions

Electronic Bypass Option Overview

General Description

During normal operation in a typical application, the input and output contactors close and the SED2 operates the motor (Figure 1). The bypass contactor provides the ability to operate the motor on utility power and eliminate the SED2 from the motor control circuit. The SED2 Electronic Bypass Option also allows you to select features that enhance the control of the contactors and the outputs that report operation.

The SED2 Electronic Bypass (E-Bypass) Option consists of a SED2 VFD, and a bypass enclosure with electronic controls (Figure 2). The electronic controls include:

•Controller board

•Keypad

•Step-down power transformer

•Contactors:

−Bypass

−Output

−Input (optional)

•Overload (current) relay

•Reactor (optional)

•Disconnect switch (or optional circuit breaker)

BYPASS OVERLOAD

CONTACTOR RELAY

VFD0093R1			VFD			MOTOR
	CONTACTOR			CONTACTOR
		INPUT			OUTPUT

Figure 1. Functional Block Diagram of

Typical Electronic Bypass Option.

CONTROLLER	SED2 VFD
BOARD

KEYPAD (DOOR

MOUNTED)

		INPUT
		CONTACTOR
	STEP-DOWN
	POWER	REACTOR
	TRANSFORMER
		(OPTIONAL)
	OUTPUT
	CONTACTOR
	BYPASS
	CONTACTOR
		DISCONNECT
		SWITCH
VFD0094R1		(OR OPTIONAL
	OVERLOAD	CIRCUIT BREAKER
		SHOWN)
	(CURRENT)
	RELAY

• Fuses (optional) Figure 2. Typical SED2 E-Bypass Components.

•Cable harnesses

4 Siemens Building Technologies, Inc.