Re: Electrical systems

Posted by HH56 On 2023/2/10 12:17:52
Some info for those not too familiar with Packard and the electric motors they used.

Original starters and in fact, most if not all Packard original single direction motors do not care about polarity as they are wired internally to always have the armature and field coils retain the proper magnetic relationship for the desired rotation. If polarity switches externally the internal magnetic relationship also changes but wiring connections between the field and armature ensure they both flip at the same time so rotation is constant. Evidence this by the many accidental and some intentional changes from positive to negative ground where nothing amiss is noted.

While they did use a couple of conventional reversible motors that need special switches or relays to change direction, for the most part Packard reversible motors work somewhat differently. MOST reversibles that Packard used had two wires and the case mounted to body metal provides the ground. On those motors ONLY ONE WIRE at a time is connected to power. To reverse direction, the first wire disconnects and the other wire gets the power. Those motors are also not polarity sensitive.

If the car has a replacement permanent magnet starter such as the mini torque used with one of the Bendtsen adapters or any other permanent magnet replacement type motor which have mostly replaced field coil motors in modern cars, those are most definitely polarity sensitive. Only the armature has coils and those coils will reverse magnetic attraction if polarity is changed. With the permanent magnet field staying the same and armature reversing, those motors will run backwards with a switch in polarity.

This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=253790