Protection Considerations - Eaton Cutler-Hammer AMPGARD Technical Data Manual

Protection Considerations

Coordinated with the motor's characteristics, the protective devices
in the Cutler-Hammer AMPGARD starter provide motor protection
from overload to full system capacity faults.
AMPGARD starters are supplied with an adjustable thermal overload
relay as standard. The overload relay is designed to protect the motor
from sustained overloads. A Cutler-Hammer GroundGard relay is an
available option for protection from ground faults. The factory setting
for the GroundGard will initiate a starter trip at approximately 7
amperes ground current.
Multi-function solid-state motor protection relays are a common
option on AMPGARD starters. The Cutler-Hammer MP-3000 is
typically provided when a multi-function relay is specified. The MP-
3000 provides many types of protection including overload, locked
rotor, ground fault and phase loss/phase unbalance. The MP-3000
also provides start control logic to protect the motor against exces-
sive starting. The relay may be applied to either across-the-line or
reduced voltage starters. On reduced voltage starters, the MP-3000
can control the transition from reduced to full voltage, offering the
greatest protection for the motor and starter. An optional RTD module
can be supplied for motors with built-in RTDs.
MP-3000 Motor Protective Relay
InsulGard relays are an available option on AMPGARD starters. The
InsulGard provides early warning of increasing partial discharge levels
in the starting equipment, cables and motor. This early warning will
help the user to better schedule maintenance and avoid unplanned
downtime.
EATON CORPORATION Cutler-Hammer Chiller Starter (AMPGARD) Technical Data TD02003003E
Ultimate Trip
Full Load Amps
Motor Starting Curve
Asymmetrical
Offset Compensation
Contactor Interrupting
Capacity
FIGURE 5. FULL RANGE COORDINATED PROTECTION BETWEEN
CURRENT LIMITING TYPE CLS FUSES, VACUUM CONTACTOR AND
MOTOR PROTECTION RELAY
MP-3000 Motor Protection
Curve Programmed to
Follow Specific Motor
Damage Curve – Providing
Maximum Motor
Utilization
Controller Maximum
Interrupting Rating
Instantaneous
Overcurrent
24R Fuse
Contactor Dropout
Current
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