Over/Under Voltage; Rtac Chillers; Check Out Procedure For Rtac; Under/Over Voltage Transformer Checkout - Trane RTHD Troubleshooting Manual

RTAC Chillers

Check out procedure for RTAC

WARNING
Live Electrical
Components!
Under/Over
Voltage
Transformer
Checkout
30

Over/Under Voltage

The under/over voltage protection is an optional configuration for RTHD and
standard for RTAC. The input voltage for the Optional Under/Over Voltage
Transformers will be supplied from the incoming (line side of the starter
contactors) three phase power connections to the unit. The secondary or these
transformer(s) are connected to the Starter module.
Over Voltage: Trip: 60 seconds at greater than 112.5%, ± 2.5%, Auto Reset at
109% or less.
Under Voltage: Trip: 60 seconds at less than 87.5%, ± 2.8% at 200V or ± 1.8% at
575V, Auto Reset at 90% or greater.
CH530 monitors one line to line voltage for the entire chiller. Regardless of how
many compressors, power supply disconnects or power terminations or starter
panels are on the unit, the design uses a single Potential Transformer of Phases
L1 to L2(Vab) wired just upstream of the contactor for compressor 1A. Under /
Over voltage protection is based solely on this voltage. The transformers will
display the magnitude of these voltages as well as provide under and over
voltage protection, if it is enabled.
During installation, testing, servicing and troubleshooting of this product, it may
be necessary to work with live electrical components. Have a qualified licensed
electrician or other individual who has been properly trained in handling live
electrical components perform these tasks. Failure to follow all electrical safety
precautions when exposed to live electrical components could result in death or
serious injury.
1 Locate the Under/Over Voltage Transformer 1T9 in the panel by referring to
the Component Location Drawing. Carefully measure and record the primary
voltage across the Transformer (Line Voltage Phase A to B).
2 Next, disconnect the transformer's secondary from J5 on the Starter module.
Using voltmeter probes, measure and note the unloaded secondary voltage
(Vac rms).
3 The ratio of the primary or line voltage to the open circuity secondary voltage
should be 20 to 1. If the unloaded turns ratio is not within 2% of this value,
replace the transformer.
4 Reconnect the secondary back to J5 and measure the loaded (connected)
secondary voltage. The new loaded ratio should be approximately 20.2 to 1. If
not within 2% of this ratio, the transformer's secondary should be
disconnected from the Starter module and a 1000 Ohm resistor connected
RLC-SVD05A-EN