Mechanical / Electrical connection
Installation & Maintenance
Mechanical
Drain holes
Prior to installation remove drain plugs if fitted. If
any water has accumulated, the integrity of all
gaskets, sealants etc. should be checked. Drain
plugs should be put back into place after draining.
Alignment
When the application calls for direct coupling, the
shafts must be correctly aligned in all three planes.
Bad alignment can be a major source of noise and
vibration. Allowance must be made for shaft
end-float and thermal expansion in both axial and
vertical planes. It is preferable to use flexible drive
couplings.
Noise levels
The noise levels published in current Sales
Specifications are equal to or less than the limiting
values for rotating machines specified International
Standards IEC 60034-9.
In most cases noise levels also meet limiting values
for exposure to noise in the work place.
It is the responsibility of the purchaser to ensure
that other overriding lower noise levels if required,
eg Machinery Directive, are specified at the time of
order, or that the installation incorporates noise
attenuating measures.
Free rotation
The shaft must be free to rotate.
Where uneven or bumpy rotation occurs the
bearings should be inspected to establish that they
have not been damaged during transportation or
storage.
B14 (IM3601) & B34 (IM2101)
Where a motor is fitted with a ‘C’ face flange, ie B14
or B34 mounted, care must be taken to ensure
mounting bolts do not protude beyond the ‘C’ face
casting thickness. See table 2.
Electrical connection
The connection diagram is shown on the leaflet
enclosed in the motor terminal box or the diagram
inside the terminal box lid (copy on page 5).
The cables used should be capable of carrying the
full load current of the motor (see motor
name-plate) without overheating or excessive
voltage drop under starting conditions.
Cable terminations
All cable terminations should be tightly secured
(see Table 3 for tightening torques).
Mains lead terminal lugs should be in face to face
contact with the motor lead lugs and securing nuts
and lockwashers screwed firmly over the
connection (where possible).
There should be no nuts or lockwashers fitted
between the mains and motor lugs.
Wiring should be carried out or checked by a
qualified electrician and equipment must be
earthed in accordance with current regulations.
The equipment must be correctly fused and
isolated.
Supply
It is important that a motor is operated within the
limits of its design voltage and frequency.
Standard motors for the UK will operate without
damage on any voltage in the range 94% to 106%
of the nameplate voltage.
The supply cables must be capable of carrying the
full load current of the motor (see motor name-
plate) without overheating or excessive voltage
drop under starting conditions.
Earthing
All motors are fitted with an earthing terminal, in
or adjacent to the terminal box, to enable connec-
tion to an effective earthing bond. The terminal is
designed for connecting the correct size of copper
earth connector. If a different material is to be
used please refer to Brook Crompton.
The motor must be earthed by connecting the
shortest possible length of cable to the earth
terminal.
The cable must have a capacity at least that
of the main connections up to 16mm² phase
conductors. Between 16 and 35mm² phase
conductors, the earth should be a minimum of
16mm² . Above 35mm² phase conductors, the
earth conductor should be a minimum of half the
phase conductor.
An earthing bond should not be terminated under
the motor fixture bolts or terminal cover screws.
The earth lead could be over-looked on
reconnection after maintenance
Auxiliary electrical items (where fitted).
Heaters should be checked for continuity prior to
connection to their appropriate supply.
Heaters must be switched off when the motor is
running.
Thermistor continuity (PTC):
Do not apply a megger across the thermistor.
Do not apply more than 6V across the thermistor.
It is recommended that thermistors are connected
to an appropriate protection relay.
(Thermistors provide good thermal overload
protection).
Resistance Temperature Detector (RTDs) should
have rsistance checked against manufacturers
data.
Thermostats (PTO)
These are ‘Normally closed’ device for connection
into the motor control circuit.
It is imperative that any overload trips and
emergency shutdown circuits are working
correctly before the motor is energised.
All covers must be in position.
Where a motor is fitted with a separately driven fan
unit, the interlocks and thermal overload
protection circuits must be operative.
Connection diagrams
Refer to the motor rating plate for supply details
for the required winding connection.
80 - 112 M4 0.8 - 1.4
132 M5 1.5 - 3.5
160 - 180 M6 3 - 6
200 - 225 M8 5.8 - 8.5
250 - 280 M10 10 - 16
315 - 355 M12 16 - 25
Frame size Terminal size Torque (Nm)
Table 3 - Terminal tightening torques
All covers must be in position prior to running.
WARNING
Isolate power supply to motor before
commencing any routine cleaning or maintenance
work.
Drying out procedures
It is preferable to dismantle the motor to the point
where the rotor is removed. This is not essential
but the drying out process will take longer in the
assembled state.
The temperature of the windings and the
insulation resistance should be monitored at
regular intervals.
On initial application of heat the insulation
resistance will drop quickly and then start to rise
slowly until level. On discontinuation of the drying
process, a further rise in resistance will occur.
There are several methods which can be used:
1place the motor in a warm (typically 40°C), dry
airstream (fan or convector heater) or in a warm
oven with a temperature not exceeding 80°C. This
method is preferred if the motor is dismantled.
2connect the motor to a low voltage* three phase
supply and inject a current not exceeding 50% of
the full load current into the stator winding
(*approximately 10% of the line voltage). If this is
carried out on an assembled motor, it is possible
though unlikely that the motor will turn. If so the
rotor should be locked in position.
3connect two phases in parallel, and the third in
series. Apply a low voltage a.c. or d.c. supply up to
a maximum of 50% of full load current. The stator
winding temperature must not be allowed to
exceed 80°C. In practice the frame should not be
hot to the touch, to guard against internal
overheating and consequent damage to the
insulation.
4where heaters are fitted these can be
energised.
80 12 mm
90 to 112 16 mm
132 20 mm
160 24 mm
Frame size casting thickness ‘LA’
Table 2 - C face casting thickness
LA
