Shoot - right when I thought I had this 2-speed wiper electronics thing
understood I read the following at a Jag site..
[The (DR1 2-speed wiper motor) armature is multi-pole and the magnetic field
is generated from a field winding. The second, faster, speed is achieved
by reducing the field current with a series resistor. A popular misconception
is that the resistor is in circuit for the slower speed. This is incorrect.
Reducing the field current reduces the magnetic flux. This has the effect of
making the motor run faster but with reduced torque. The physical form of the
resistor is a few turns of resistance wire wound around the field coil. For 12
volt versions of this unit the speed control resistor is 12 - 14 ohms and the
resistance of the field winding itself, approximately 8 ohms. Normal running
current is about 3 amps.]
Now I think I can understand Ed's description better and will not try to
rewrite it! (Thanks again Ed!)
Carl
'63 TR4 since '74
Anyone that's still interested,
Spent the evening trying to figure out how the 2 speed wiper worked. Finally
figured out the that second "winding" isn't a field winding at all. It's
just a resistance wire that,
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