369 Motor Management Relay Instruction Manual

scheme. This section will cover most of the typical 369 interconnections.

In this section, the terminals have been logically grouped together for explanatory purposes. A typical wiring diagram for

the 369 is shown above in Figure 3–4: TYPICAL WIRING on page 3–6 and the terminal arrangement has been detailed in

Figure 3–3: TERMINAL LAYOUT on page 3–5. For further information on applications not covered here, refer to Chapter 7:

APPLICATIONS or contact the factory for further information.

Hazard may result if the product is not used for intended purposes. This equipment can only be serviced

by trained personnel.

The 369 has a built-in switchmode supply. It can operate with either AC or DC voltage applied to it.

Extensive filtering and transient protection has been incorporated into the 369 to ensure reliable operation in harsh industrial

environments. Transient energy is removed from the relay and conducted to ground via the ground terminal. This terminal

must be connected to the cubicle ground bus using a 10 AWG wire or a ground braid. Do not daisy-chain grounds with

other relays or devices. Each should have its own connection to the ground bus.

The internal supply is protected via a 3.15 A slo-blo fuse that is accessible for replacement. If it must be replaced ensure

that it is replaced with a fuse of equal size (see FUSE on page 2–4).

The 369 requires one CT for each of the three motor phase currents to be input into the relay. There are no internal ground

connections for the CT inputs. Refer to Chapter 7: APPLICATIONS for a information on two CT connections.

The phase CTs should be chosen such that the FLA of the motor being protected is no less than 50% of the rated CT primary.

Ideally, to ensure maximum accuracy and resolution, the CTs should be chosen such that the FLA is 100% of CT primary

or slightly less. The maximum CT primary is 5000 A.

The 369 will measure 0.05 to 20 ´ CT primary rated current. The CTs chosen must be capable of driving the 369 burden

(see specifications) during normal and fault conditions to ensure correct operation. See Section 7.4: CT SPECIFICATION

AND SELECTION on page 7–7 for information on calculating total burden and CT rating.

For the correct operation of many protective elements, the phase sequence and CT polarity is critical. Ensure that the convention

illustrated in Figure 3–4: TYPICAL WIRING on page 3–6 is followed