Checking Motor And Cable; Disposal - Grundfos BMEX Series Montage- Und Betriebsanleitung

23. Checking motor and cable

1. Supply voltage
2. Current consumption
Points 3 and 4: Measurement not needed if supply voltage and current consumption are normal.
3. Winding resistance
4. Insulation resistance

24. 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.
24
Measure the voltage between the phases with
a voltmeter.
Connect the voltmeter to the terminals in the
motor starter.
Measure the current of each phase while the
module is operating at a constant discharge
pressure (if possible at the capacity where the
motor is most heavily loaded).
For normal operating current, see the
"Technical specification".
Remove the phase leads from the terminal
box.
Measure the winding resistance as shown on
the drawing.
Remove the phase leads from the terminal
box.
Measure the insulation resistance from each
phase to earth (frame).
(Make sure that the earth connection is made
carefully.)
Subject to alterations.
The voltage should, when the motor is loaded, be
within ± 5 % of the rated voltage. The motor may burn
if there are larger variations in voltage.
If the voltage is constantly too high or too low, the
motor must be replaced by one corresponding to the
supply voltage.
Large variations in the supply voltage indicate poor
power supply, and the module should be stopped until
the defect has been found.
Resetting of the motor starter may be necessary.
The difference between the current of the phase with
the highest amp consumption and the one with the
lowest amp consumption must not exceed 10 % of the
lowest amp consumption.
If so, or if the current exceeds the rated current, check
these possible faults:
• A damaged pump is causing the motor to be
overloaded. Pull the pump out of the sleeve for
overhaul.
• The motor windings are short-circuited or partly
disjointed.
• Too high or too low supply voltage.
• Poor connection in leads. Weak cables.
The highest value must not exceed the lowest value by
more than 5 %.
If the deviation is higher and the supply cable is OK,
the motor should be overhauled.
The insulation resistance for a new, cleaned or
repaired motor must be approx. 10 MΩ measured to
earth.
For a given motor the critical insulation resistance
(R ) can be calculated as follows:
crit
R = U [kV] x 0.5 [MΩ/kV].
crit N
If the measured insulation resistance is lower than
R , the motor must be overhauled.
crit