TR5/TR250 Switching a TR3 wiper motor over to a TR250

[Got_All_4]

My 2 speed wiper motor burned up last year and searching for another motor was impossible. Scott at Team Triumph sold me a TR3 motor which are the same except I will only have 1 speed.

Switched out the guts, prettied it up then tried to put power to it and nothing. Ground wire to the casing and briefly touched # 1 & 2 terminals with no results. Before I burn this motor by mistake what should # 1 & 2 terminals be hooked to? The TR3 Hains manual only shows a wire from the switch to the motor.

 

[Got_All_4]

Well I figured it out. Sitting next to the 250 is my TR3A. Dah! " It takes a littler longer for some of us to figure things out but we make some of the finest mechanics in the world" So I took my multi meter to it and discovered the # 1 terminal goes to ground . It shows this in the TR4 schematics too. Put power to #2, grounded #1 and the ground wire and wallah. It's alive!

 

[TR3driver]

Are they really the same ? I would have thought the TR250 wipers had a wider sweep (meaning the gear inside the motor is different); but I've never checked.

 

[Got_All_4]

Yes your correct. The travel on a TR3 motor is 110 degrees. 120 on a Tr250 because of the larger windshield. I only replaced the armature and field coil and left the large gear in.

My only concern now is the 3 has a positive ground so will the motor turn backwards? Thinking this through it only makes the cable go back and forth. The resting position may be 180 degrees off. I'll find out when I turn on for the first time. If I wipe my hood I'll have to switch polarity.

 

[TR3driver]

The TR3 motor (unlike the later ones) has a wound field, so turns the same direction regardless of which polarity is applied. The motor type is known as a "universal" motor, it will even run on AC !

Of course as you note, it only moves the cable back and forth, so it doesn't matter to the wiper mechanism which way the gear turns. But the park switch and thrust bearings inside the motor are set up for a particular direction, so it would wear quickly if it were to run backwards.