Bard WG3S1-A WG3S1-B WG3S1-CWG4S1-A, Installation Instructions Manual

Page: 41 / 59

Manual 2100-483E
Page 41 of 59
THREE PHASE SCROLL COMPRESSOR
START UP INFORMATION
Scroll compressors, like several other types of
compressors, will only compress in one rotational
direction. Direction of rotation is not an issue with
single phase compressors since they will always start
and run in the proper direction.
However, three phase compressors will rotate in either
direction depending upon phasing of the power. Since
there is a 50-50 chance of connecting power in such a
way as to cause rotation in the reverse direction,
verification of proper rotation must be made. All three
phase units incorporate a phase monitor to ensure
proper field wiring. See the “Phase Monitor” section in
this manual.
Verification of proper rotation must be made any time
a compressor is change or rewired. If improper rotation
is corrected at this time there will be no negative
impact on the durability of the compressor. However,
reverse operation for over one hour may have a
negative impact on the bearing due to oil pump out.
NOTE: If compressor is allowed to run in reverse
rotation for several minutes, the
compressor's internal protector will trip.
All three phase ZPS compressors are wired identically
internally. As a result, once the correct phasing is
determined for a specific system or installation,
connecting properly phased power leads to the same
Fusite terminal should maintain proper rotation
direction.
Verification of proper rotation direction is made by
observing that suction pressure drops and discharge
pressure rises when the compressor is energized.
Reverse rotation also results in an elevated sound level
over that with correct rotations, as well as, substantially
reduced current draw compared to tabulated values.
The direction of rotation of the compressor may be
changed by reversing any two line connections to the
unit.
See “Phase Monitor”, Page 33.