WEG BFGC 250-315 Instructions De Service page 16

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.
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 follo-
wing table:
TEMPERATURE
Should the insulation resistance values be lower than the above, check if the terminals are
affected by humidity or dust and clean them as necessary.
In the event of this not being the case the motors will need to be oven dried at a temperatu-
re less than 100 º C degrees.
5.2 Ensure that the motor nameplate voltage is the same as the mains supply. The connection
diagrams supplied inside the motor terminal box shall be always respected in function of
available supply voltage and/or required speeds (2 speed motors).
For information, the most common connection diagrams are indicated on pages
16
U V
WINDING
20º C
30º C
40º C
W
10 MΩ 200 MΩ
5 MΩ 100 MΩ
Português - English - Français
Insulation tester
VOLTAGE SERVICE
< 1,1KV > 1,1KV
20 MΩ 400 MΩ
33-34.