2202L5JE-DA-C5-N_2015.05.
5 Maintenance and Inspection
Compound 2-stage Screw Compressor
5.5
Reassembly
1612LSC Speed Increaser Type
5-69
5.5.14 Unloader
Indicator
The unloader indicator contains micro-switches, a micro-switch cam and a potentiometer. Either of
them detects the rotational volume change of the shaft of the indicator cam, which converts the axial
positional change of the unloader slide valve into circumferential positional change, and sends it as
electric signals to the control side of the package unit or refrigerating system.
For confirmation after inspection/adjustment or parts replacement, they need to be linked with the
control side. So, even during an overhaul which is conducted with the compressor carried out of the
installation site, this portion is often removed from the compressor as an indicator assembly so that
inspection/adjustment or parts replacement can be conducted at the site.
When testing/adjusting or replacing parts on the indicator, make sure to turn off
and lockout/tagout the control power. Failure to do so could cause an electric
shock.
The 1612**C models have, on its low-stage, an indicator designed for the low-stage of 2-stage
compressor, which, additively, has a bevel gear for changing the indicator needle and dial from axial
direction to lateral direction.
Figure 5-19 Development View of the 1612**C Unloader Indicator
