Disconnect Means. Trane Drives, CVHG, Starters, CVHF, Electrical Components, CVHE, CDHG, CDHF

CTV-PRB004.book Page 52 Sunday, December 18, 2011 6:39 PM

Electrical System—Design Guidelines

Figure 39. Electrical rating label locations

AFC—available fault current

Three-phase line power

SCCR—starter short-circuit current rating

AIC—circuit breaker ampere-interrupting rating

Starter door

There are three functions that electrical engineers must address when designing electrical systems that include chiller motors and the associated starters:

1.

Means of disconnect

2. Means for short circuit interruption

3. Making sure that the starter enclosure has an adequate short-circuit current rating for the available fault current (low voltage) or properly sized fuses (medium voltage)

Disconnect Means

Low-voltage disconnect

Low-voltage starters from Trane do not have a disconnect means as standard. The standard line power connection is a terminal block (i.e., main lug only) connection. An optional non-fused disconnect switch, in a molded case as shown in Figure 40 , can be installed. These non-fused disconnect switches typically have locking provisions to allow the switch to be locked open; often with up to three different padlocks.

Figure 40. Non-fused disconnect

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A non-fused disconnect switch is used when servicing the chiller to protect someone from personal injury, and it can also be used as a load-break switch in an emergency. Since the disconnect switch is a non-fused device, current limiting protection must be installed upstream of the chiller by others.

CTV-PRB004-EN