14
15GDS/20GDS Installation, Operation and Maintenance Manual
Under no circumstances may the starter equipment be installed in the sump.
NOTE: For safety reasons, the earth conductor should be approximately 2.0” (50 mm)
longer than the phase conductors. If the motor cable is jerked loose by mistake, the earth
conductor should be the last conductor to come loose from its terminal. This applies to both
ends of the cable.
Thermal contacts are incorporated in the stator. The thermal contacts can be connected to
maximum 250 V, breaking current maximum 4 A. Bell & Gossett recommends that they be
connected to 24 V over separate fuses to protect the other automatic equipment.
Make sure that the pump is correctly earthed (grounded).
When using a variable-frequency-drive (VFD) special rules have to be followed to avoid
clogging and over-heating. Contact your VFD supplier and ask for electrical limitations.
Remember that the starting current in direct online starting can be up to six times higher
than the rated current. Make sure that the fuses or circuit breakers are of the proper rating.
The Parts List gives rated current. Fuse rating and cable shall be selected in accordance with
local rules and regulations. Note that with long cables, the voltage drop in the cable must be
taken into consideration, since the motor’s rated voltage is the voltage that is measured at
the terminal board in the pump.
The overload protection (motor protection breaker) for direct online starting shall be set to
the motor rated current as given on the data plate.
Check the phase sequence in the mains with the phase sequence indicator.
If intermittent operation is prescribed (see Data Plate), the pump shall be provided with
control equipment that provides such operation.
Single Phase Operation
The single phase pumps must be equipped with a starter which has start and run capacitors.
A special designed starter is required for the operation of single phase pumps. The
connection of the motor cable to the starter is shown in the wiring diagram.
NOTE: It is not possible to change the direction of rotation of a single phase pump by
changing the cable conductors on the starter. Please contact your nearest Bell & Gossett
representative.
Monitoring Equipment
The FLS sensor consists of a small float switch for sensing water in the stator housing. Its
design makes it suitable for pumps in vertical installations. The FLS sensor is installed in the
bottom of the stator housing.
The MiniCas II is a monitoring relay to which FLS is connected.
Check:
• signals and tripping function.
• that relays, lamps, fuses and connections are intact.
Replace defective equipment.
Electrical Connections (continued)
