NEGATIVE TERMINALS

NEGATIVE TERMINALS

'Block connectors' are useful for connecting the wires from the stator. Alternatively soldering or crimping would be fine.

Use solder, or crimped 'receptacle' connectors, to connect wires to the rectifiers. Take care not to overheat the rectifiers while soldering. Bolt the rectifiers onto the heatsink, which will probably look like the one in the diagram, but can be any piece of aluminium approximately 250 grams or more in weight.

Keep all the connections under a weatherproof cover.

Two bridge rectifiers

 

Testing and connecting

Check that the PMG has no faults before it is put into use. It will be much easier to correct the faults now, than to return the unit to the workshop later.

Mechanical testing

Mount the spine vertically in a vice. The magnet rotors are free to move. The shaft is horizontal, as it will be in a wind generator. Check that the wires are not touching each other, creating a short circuit which makes the PMG harder to turn.

Check that the rotor will spin freely.

Spin the rotor and listen for sounds. There should not be any scuffing or brushing of the rotor, as it turns. It should spin freely for several seconds and gradually come to a halt. If it slows down rapidly then there may be an electrical fault, or the bearings may be over-tightened.

Grasp the stator with both hands. Push one side backward while pulling the other side forward, while the rotor is spinning. It must not touch the rotor. If there is a rubbing sound, then it may be necessary to disassemble the PMG and assemble it more carefully, with more space between the rotor and the stator. Or it may be possible to correct the problem by making minor adjustments to the stator mounting studs.

Stop the rotor with one of the studs in the 3 o'clock position (diagram 43). Hang an object weighing 1 00 grams on this stud. The rotor should begin to turn clockwise. If it will not turn, then the bearings may be over-greased or too tight.