Watson-Marlow 900 Series - Manual (Page 6)

Page 6
Electrical connection
In order to effectively protect the motor from overloads, appropriate motor
protection devices must be used. Motors fitted to the Watson-Marlow series of
pumps are manufactured with a motor temperature cut-out, but a current
overload relay should also be fitted to a contact breaker.
The motor should be connected by a qualified engineer who is
conversant with the appropriate regulations and they should ensure that
the voltage and frequency of the electrical supply corresponds with the
data on the motor plate.
Connect the motor in accordance with the wiring diagram which will be found
in the motor terminal box.
When a motor thermal protection switch is fitted in the motor, the leads will be
found in the motor terminal box. They should be connected to stop the pump if
the switch operates. The switch will open circuit at an over temperature
condition.
The diagram below shows the connection of the drive motor showing possible
ancillary switches and protections. It depends on the installation whether a
reversing switch and interlock with other equipment is included.
Care must be taken to ensure that
the motor terminal links are in the
correct position and that all
connections including the earth
connection are positioned
correctly and securely.
Ingress protection standard will be
compromised if the connection
box cover is not properly replaced
or if the cable gland is not
correctly fitted. Exd motors must
be connected with approved fitting
and practice.
All pumps, excluding those
intended for use in hazardous
atmospheres, may be fitted with a
door indicator switch. This switch
is rated 240V 0.5A AC Max. Power
load 50W Max. This switch is NOT
intended as a primary safety
device. Under normal operation the
pump door is kept closed and this
meets all statutory requirements
as a tool lockable fixed guard.
The switch may be used directly to
indicate that the door is open
during maintenance, or it may be
wired, following accepted fail safe
practices, into a customers start
up/shut down control system to
provide a back up to the Fixed Guard, whilst maintenance is being
carried out. However, all normal maintenance safety practices should
also be observed.
There are dangerous voltages (at mains potential) inside the motor. If
access is required, isolate the pump from the mains before removing the
cover.