Troubleshooting | 11
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Problem
Possible Cause
Remedy
The vacuum pump does not
start.
The motor is not supplied
with the correct voltage.
• Check the power supply.
The motor starter overload
settings are too low or trip
level is too low.
• Check overload settings in
motor starter for size and
set according to motor
nameplate data.
A fuse is blown.
• Check the fuses, replace if
necessary.
Connection wiring is too
small or runs are too long
causing too great a voltage
drop.
• Use proper wire size.
Pump or motor is seized.
• Remove fan cover and try
to turn the pump and
motor by hand. If frozen,
remove motor from pump
and check motor and
pump separately. If pump
is frozen, contact Busch
service.
The motor is defective.
• Replace the motor.
The coupling (CPL) is defec-
tive.
• Replace the coupling
(CPL).
The vacuum pump starts,
but labors and draws a very
high current.
Vacuum pump runs in the
wrong direction
• Swap any two motor
leads
Vacuum pump is overfilled
with oil or wrong kind of oil
is used
• Correct the oil level and
quantity per
Technical
Data Table [
►
27]
.
Exhaust filters in exhaust
chamber are clogged and
appear to be burned black
with pump oil
• Replace exhaust filters.
Maintain proper oil condi-
tion and oil level, and use
only Busch recommended
vacuum oil.
The exhaust filter is clogged
due to process material
• Contact Busch for process
recommendations
Loose connection in motor
terminal box; not all motor
coils are properly connected.
Motor operates on two
phases only.
• Check motor wiring dia-
gram for proper hookup,
especially on motors with
six internal motor wind-
ings. Tighten and/or re-
place loose connections.
Vanes broken
• Contact Busch service.
Seized bearing
• Contact Busch service.
Foreign object in pump
• Remove foreign object
