Preliminary Checks - Grundfos VersaFlo UPS Installation And Operating Instructions Manual

Fault
7. Single-phase
pumps with protec-
tion module (only).
The pump does not
run.
The red indicator
light is on.
The green indicator
light is off.

5.2 Preliminary checks

Supply voltage
To check the voltage being supplied to the motor,
use a voltmeter.
WARNING!
Be careful, since power is still being sup-
plied to the pump. Do not touch the volt-
meter leads together while they are in con-
tact with the power lines.
Single-phase motors
Touch one voltmeter
lead to each of the lines
supplying power to the
pump:
• L and N for 115 V
circuits
• L1 and L2 for 230 V
circuits.
L L
1 2
Fig. 18 Checking single-phase power
12
Cause
a) The pump has been cut out
by the thermal overload
switch due to high liquid
temperature or blocked
rotor.
b) The speed switch module
has not been fitted.
Three-phase motors
Touch a voltmeter lead
to:
• Power leads
L1 and L2
• Power leads
L2 and L3
• Power leads
L3 and L1.
These tests should give
a reading of full line
voltage.
Remedy
Check that the liquid temperature falls within the
specified range. The pump will restart automati-
cally when it has cooled to normal temperature.
NOTE: If the thermal overload switch has cut out
the pump three times within a short period, the
pump must be restarted manually by switching
off the electrical supply.
Switch off the electrical supply by means of the
external mains switch and fit the speed switch
module.
Evaluation
When the motor is under load, the voltage should be
within 10% (+ or –) of the nameplate voltage. Any
variation larger than this may indicate a poor electri-
cal supply and can cause damage to the motor wind-
ings. The motor should not be operated under these
conditions. Contact your power supplier to correct
the problem or change the motor to one requiring the
voltage you are receiving.