Current Measurement; Insulation Resistance (Lead-To-Ground); Winding Resistance (Line-To-Line) - Grundfos UPS 200 Serie Instrucciones De Instalación Y Funcionamiento

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
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.

6.5 Winding resistance (line-to-line)

To check the winding resistance of the motor
windings, 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 1, touch its leads together, and adjust
the indicator to zero.
4. Using the charts below for reference, touch
the leads of the megohmmeter to the
appropriate pair of connectors. Check all
pairs that are present and write down and
label (RA, RS , RS
1 2
5. Compare your readings to the matching
model, phase and voltage on the chart on
page 17 and page 18.
Evaluation
The resistance values must fall within the
tolerances listed on page
do not, replace the motor.
, R) all readings.
17 or page 18. If they
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