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4.8 06E Compressors: Contactor Selection and
Wire Sizing
On our larger 06E compressors, Carlyle requires that the
equipment manufacturer utilize an approved and UL rec-
ognized overcurrent device to protect the 06E compres-
sor. In this case, the must trip setting of the overcurrent
device is equivalent to the MCC for the compressor.
For the 06E example, an 06ER475, 208/230 volt model,
in combination with a Heinemann calibrated circuit
breaker, HH83XB625 was selected. This circuit breaker
has a must trip setting of 104 amperes and this ampere
value now becomes equivalent to the MCC value for this
compressor/protection combination.
This type of compressor protection combination is clas-
sified by UL as an overload relay and, therefore, the min-
imum RLA value can be determined by using the 140%
rule. Therefore, the minimum allowable RLA for this
06ER475, 208/230 volt compressor application would
be 104 divided by 1.40 or 74.3 amperes. This value
would also be the minimum ampere value Carlyle would
allow for contactor and wire sizing. This RLA value only
applies to the 06ER475 compressor protected by the
HH83XB625 circuit breaker. If other circuit breakers or
overload protection devices are used, different MCC and
RLA values would result as dictated by the must trip set-
ting of the protection device used.
The compressor Must Trip Ampere value shown in Table
6 (108 amperes for the 06ER475, 208/230-3-60 volt
model) is the maximum ampere value at which the
06ER475 (208/230 volt) compressor motor can be
operated, and the must trip setting of any circuit breaker
or overload relay must be at or below 108 amperes. The
140% rule is used to determine a maximum compressor
RLA value of 77.1 (108/1.40).
4.9 Compressor Nameplate Data
The compressor nameplate specifies voltage, phase, fre-
quency, and locked rotor current. The rated load current
shown in our specification charts may vary depending on
the overcurrent device chosen, and for that reason is not
typically printed in the space shown on the nameplate. If
required, the OEM manufacturer can stamp the appro-
priate value. The locked rotor inrush current for the first
step of part-winding start motors is shown in Tables 6 -
9 on Pages 38 and 39 for the 06E compressors. The 06D
compressors are currently not available with part-wind-
ing start motors. The allowable voltage variation at the
compressor terminals for all 06D and 06E compressors
is typically within +10 of the nominal nameplate rating
and is shown in Table 5, page 25.
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