Re: !956 Power window electric motor
Posted by HH56 On 2016/3/10 13:06:34
Quote:
The circuit I am using with the Bosch type relays is a bit different than Craigs. On the Bosch type circuit the switch only works the relay coil and relay contacts take all the load leaving the switch with very little current requirement. It will work 55 or 56 with the only change being either the switch is connected to operate the opposite relays or the motor is connected opposite. Haven't decided which method to implement.
When off, both relays normally closed contacts connect motor leads to ground and motor does nothing.
When Up is selected, UP relay energizes and connects terminal B of motor to 12v. DN relay stays relaxed so voltage goes from battery thru motor B, out A and back to ground thru DN relay normally closed contact. Motor rotates in one direction.
When Dn is selected, DN relay energizes and connects terminal A of motor to 12v. UP relay stays relaxed this time so path from B is thru UP relay normally closed contact to ground. Polarity at A and B has been switched so motor reverses.
If by chance two switches operate both relays at once the motor sees 12v on both leads so again nothing happens. This is different than the stock Packard where two switches could energize both field coils at once. In that circumstance motor does not move but current draw thru both switches is considerable.
As was mentioned earlier, PM motors are polarity sensitive so if the battery is accidentally reversed all will still function but the motor will be running opposite. Pushing the switch to lower window will try to raise it and vice versa. No electrical damage will occur but at least there will be an indication that polarity has changed.
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You guys are right about the relays only being there to reverse the polarity, not take the current load off the switches. In any case, here's a section with clearer circuit diagrams from my Panther website update.
The circuit I am using with the Bosch type relays is a bit different than Craigs. On the Bosch type circuit the switch only works the relay coil and relay contacts take all the load leaving the switch with very little current requirement. It will work 55 or 56 with the only change being either the switch is connected to operate the opposite relays or the motor is connected opposite. Haven't decided which method to implement.
When off, both relays normally closed contacts connect motor leads to ground and motor does nothing.
When Up is selected, UP relay energizes and connects terminal B of motor to 12v. DN relay stays relaxed so voltage goes from battery thru motor B, out A and back to ground thru DN relay normally closed contact. Motor rotates in one direction.
When Dn is selected, DN relay energizes and connects terminal A of motor to 12v. UP relay stays relaxed this time so path from B is thru UP relay normally closed contact to ground. Polarity at A and B has been switched so motor reverses.
If by chance two switches operate both relays at once the motor sees 12v on both leads so again nothing happens. This is different than the stock Packard where two switches could energize both field coils at once. In that circumstance motor does not move but current draw thru both switches is considerable.
As was mentioned earlier, PM motors are polarity sensitive so if the battery is accidentally reversed all will still function but the motor will be running opposite. Pushing the switch to lower window will try to raise it and vice versa. No electrical damage will occur but at least there will be an indication that polarity has changed.
Attach file:
(31.74 KB)
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