Grundfos MG, Instructions Manual

Page: 12 / 76

English (GB)
12
13. Fault finding
The table below covers the most frequent faults.
Contact Grundfos if the table does not cover the specific fault.
14. Service
All repairs must be carried out in accordance with IEC 60079-19.
Observe the provisions of EN 50110-1 until all maintenance work
has been completed, and the motor has been assembled.
14.1 Motor bearings
Take care when replacing the motor bearings.
14.2 Service documentation
Service documentation is available on www.grundfos.com >
WebCAPS > Service.
If you have any questions, please contact the nearest Grundfos
company.
15. Disposal
This product or parts of it must be disposed of in an
environmentally sound way:
1. Use the public or private waste collection service.
2. If this is not possible, contact the nearest Grundfos company
or service workshop.
Subject to alterations.
Warning
Before starting fault finding, switch off the power
supply. Make sure that the power supply cannot
be accidentally switched on.
Motor service and fault finding must be carried
out by qualified personnel.
Fault Cause
1. Motor does not start. a) Power supply disconnected.
b) Fuses blown.
c) Automatic circuit breakers cut
out.
d) Motor-protective circuit breaker
tripped.
e) Thermal protection tripped.
f)
Contacts of motor-protective
circuit breaker or magnet coil
defective.
g) Control circuit defective.
h) Blocked rotor.
i)
Motor defective.
2. Motor-protective
circuit breaker trips
immediately when
supply is switched on.
a) A fuse blown.
b) Contacts of motor-protective
circuit breaker defective.
c) Blocked rotor.
d) Cable connection loose or
faulty.
e) Motor winding defective.
f)
Motor-protective circuit breaker
setting is too low.
3. Motor-protective
circuit breaker trips
occasionally.
a) Motor-protective circuit breaker
setting is too low.
b) Mains voltage periodically too
low.
c) Voltage asymmetry
Caution
Do not expose the bearings to impacts or shocks.