WEGeuro – Indústria Eléctrica S.A.
17
U
V
W
In the case of belt drive transmissions they must be static conductive, flame
resistant and self-extinguishing. The pulleys should neither be too narrow or
wider than the width of the shaft end. The tension of the pulleys should also be
taken into account; it should not be higher than the values of radial loads
recommended for bearings. If these specifications are not followed, there is a
serious risk of collapse of the bearings or even the shaft.
4.4
Unless different engraved on nameplate, these motors are prepared to work on
ambient temperatures from -20ºC up to +40ºC.
For temperatures out of this range the factory shall be contacted, to analyse if a
special execution and/or certification is required.
4.5
In motor installation take care to ensure a free circulation of fresh cooling air is
guaranteed.
4.6
If the motor is mounted on vertical position shaft down, a protection canopy
shall be fitted on fan cowl to avoid the ingress of water or solid objects through
the fan grid protection.
5. START UP
5.1 If the motors have been out of service or stored for a long period of time, it is
recommended that the winding resistance is measured before installation and
start up.
The insulation resistance should be measured using equipment rated for 500
VDC for motor voltages up to 1,1kV, and equipment rated for 1000 VDC for
motor voltages between 1,1 kV and 11 kV.
These measurements should be made before connecting the supply cables.
A possible diagram to measure the insulation resistance for complete winding is
showed below. The measure must be taken 1 minute after apply the DC
voltage with the insulation tester.
Insulation tester
According standard IEEE 43-2000 the recommended minimum insulation
resistance values at 40ºC in MΩ are the following:
•
5 MΩ, for low voltage motors (U < 1,1kV)
•
100 MΩ, for medium voltage motors (1,1kV < U < 11kV)
Insulation resistance depends mainly from the winding temperature as showed
in the following table:
