Manitowoc Multiplex N2Fusion, Руководство по обслуживанию

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48 Part Number 020007115 06/27/2019
Component Check Procedures Section 7
COMPRESSOR ELECTRICAL DIAGNOSTICS
Location
On the base unit behind the rear panels.
Specification
R-290 220-240/50 - 1/5HP, TL4CN
Check Procedure - The compressor does not start or will
trip repeatedly on overload
CHECK RESISTANCE (OHM) VALUES
Compressor windings can have very low ohm values. Use a
properly calibrated meter.
Perform the resistance test after the compressor cools. The
compressor dome should be cool enough to touch (below
120°F/49°C) to assure that the overload is closed and the
resistance readings will be accurate.
SINGLE PHASE COMPRESSORS
Disconnect power, then remove the wires from the
compressor terminals.
The resistance values between C and S and between C and
R, when added together, should equal the resistance value
between S and R.
If the overload is open, there will be a resistance reading
between S and R, and open readings between C and S and
between C and R. Allow the compressor to cool, then check
the readings again.
CHECK MOTOR WINDINGS TO GROUND
Check continuity between all three terminals and the
compressor shell or copper refrigeration line. Scrape metal
surface to get good contact. If continuity is present, the
compressor windings are grounded and the compressor
should be replaced.
COMPRESSOR DRAWING LOCKED ROTOR
To determine if the compressor is seized, check the amp
draw while the compressor is trying to start.
The two likely causes of this are a defective starting
component and a mechanically seized compressor.
To determine which you have:
Install high and low side gauges.
Try to start the compressor.
Watch the pressures closely.
If the pressures do not move, the compressor is seized.
Replace the compressor.
If the pressures move, the compressor is turning slowly and
is not seized. Check the capacitors and relay.
COMPRESSOR DRAWING HIGH AMPS
The continuous amperage draw on start-up should not be
near the maximum fuse size indicated on the serial tag.
DIAGNOSING CAPACITORS
If the compressor attempts to start, or hums and trips the
overload protector, check the starting components before
replacing the compressor.
Visual evidence of capacitor failure can include a bulged
terminal end or a ruptured membrane. Do not assume a
capacitor is good if no visual evidence is present.
Use a capacitor tester when checking a suspect capacitor.
Clip the bleed resistor off the capacitor terminals before
testing.
If the compressor hums and will not start but the windings
are OK. Replace the start capacitor.
A good test is to install a known good substitute capacitor.