Three-phase motor wound rotor and sleeve sealing off cause analysis

Three-phase motor rotor winding and headgear desoldering is around one of the sub type rotor fault. The main reason is the welding is not completely clear, or welding. Therefore, the increase of contact resistance, electric heating after the solder melting, resulting in winding is inserted into the guide bar and headgear desoldering.

Before welding inspection can be carried out in the following ways:

1 careful observation of the wound rotor head set all wrong solder off or discoloration.

. with a small hammer tap and hoods beat not too heavy, so as not to damage the insulation), if it is found that the removing tin, welding parts, yellowish brown, or hammering a hoarse voice and loose phenomenon indicate that the winding into the bar and the guide and headgear needs to be welded again.

3 and hoods of welding failure, if the observation with the naked eye can not be determined, use a bridge to measure the interphase resistance, find out the resistance value is too large for the one or two phases, and is the bridge accurate to refer to zero, and then use soft wood or laminated board one by one leveraging this one phase or two-phase and headgear, observing the bridge pointer, if leveraging a head set pointer deviation from zero, it indicates that the headgear contact bad.

4 power check. This is the most accurate method for checking. Check the current (equivalent to the rated current of the welding current) to the rotor winding, and the 10-15min, with the hand to touch the welding parts. If welding is good, welding parts and other parts of the heat are the same; if bad welding, welding parts of a serious fever, high temperature, this can be done in the heat of the site, ready to fill welding.