Table of Contents
Advertisement
2–24
Courtesy of NationalSwitchgear.com
FIGURE 2–5: Core Balance Ground CT Installation (shielded cable)
OUTPUT RELAYS
There are 4 output relays each with form C contacts (normally open (NO), normally closed
(NC), and common (COM)). Contact ratings for each relay are identical and are listed in
Section 1.2: Specifications. FIGURE 2–3: Typical Wiring Diagram on page 2–20 shows the
state of the relay contacts with no control power applied; that is, the relays are not
energized. Relay contact wiring will depend on how the relay operation is programmed in
(see Section 4.4: S3: Output Relays on page –24).
S3:OUTPUT RELAYS
Relay contacts must be considered unsafe to touch when the system is energized. If the
relay contacts are required for low voltage accessible applications, it is the customer's
responsibility to ensure proper insulation levels.
•
TRIP RELAY (23/24/25): Wiring of the trip relay contacts will depend on whether a
breaker or contactor is the motor tripping device and if failsafe or non-failsafe
operation is desired. See programming considerations for the trip relay in Section
4.44.4.1 Trip Relay on page 4–25.
Contactor: For maximum motor protection, program the trip relay to be failsafe
and wire the contactor to the NO/COM trip relay terminals. When control power is
lost to the 239, the contactor will trip to ensure maximum protection. If process
CHAPTER 2: INSTALLATION
239 MOTOR PROTECTION RELAY – INSTRUCTION MANUAL
Advertisement
Table of Contents
