Current Measurement; Insulation Resistance (Lead-To-Ground) - Grundfos UPS 200 Serie Instructions D'installation Et D'utilisation

6.3 Current measurement

To check the current, use an ammeter.
To do so, follow these steps:
1. Make sure the pump is operating.
2. Set the ammeter to the proper scale.
3. Place the tongs of the ammeter around the
leg to be measured.
4. Compare the results with the amp draw
information on the motor nameplate.
5. Repeat for the other legs.
Evaluation
If the current draw exceeds the listed nameplate
amps, or if the current imbalance is greater than
5% between each leg on three-phase units, then
check the following:
• The voltage supplied to the pump may be too
high or too low.
• The contacts on the motor starter may be
burned.
• The terminals in the starter or terminal box
may be loose.
• There may be a winding defect. Check the
winding and insulation resistance.
• The motor windings may be shorted or
grounded.
• The pump may be damaged in some way
and may be causing a motor overload.
• A voltage supply or balance problem may
exist.
Fig. 18
Current measurement
12
6.4 Insulation resistance
(lead-to-ground)
To check the insulation resistance
(lead-to-ground) of the motor and leads, a
megohmmeter is required.
To do so, follow these steps:
1. Turn the POWER OFF.
2. Disconnect all electrical leads to the motor.
3. Set the scale selector on the megohmmeter
to R x 100K, touch its leads together, and
adjust the indicator to zero.
4. Touch the leads of the megohmmeter
individually to each of the motor leads and to
ground (i.e. L1 to ground; L2 to ground, etc.).
Fig. 19
Insulation resistance measurement
Evaluation
The resistance values for new motors must
exceed 1,000,000 ohms. If they do not, replace
the motor.