Moss Motors, Ltd

I just purchased a Lucas wiper motor off Ebay, advertised for a Sprite. Don't know what year. This is a replacement for my English Ford so no wiring diagram available. This turned out to be a 5 wire instead of 4 wire motor so I'm not sure what the three striped wires are for. Anyway, the wires cut off from the motor are Green, Black, Brown/Green, Red/Green and Blue/Green. Could this be a 3 speed instead of the 2 that I expected? Any advice as to their respective purpose will be greatly appreciated. I don't want to just experiment and cause the smoke to escape.

 

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

Hey enfoprefect,

Not sure i can help at all, but i would seriously be interested in hearing the answer - that is, if this wiper motor is for your '67 Sprite...  I just picked up a '67 last monday and having never done a restore before, could sure use all the help i can get....

take care,

Lou

Springfield, OR  (loumeg@msn.com)

 

enfo,

I'm pretty sure you've got a two speed, three brush unit there. Black is, of course, ground. I think you'll find the solid green is the park function wire. You may need a manual showing switch layout to translate for use in your car. The proper switch for this motor has four terminals used from an eight terminal plug!

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Thanks for the quick reply Bill. Unfortunately, there is no wiring diagram available for my Prefect. According to my Haynes Spridget manual, it looks like I have a motor from about a '67 onwards car. Actually, it may be even later as the connector is a fairly modern looking plastic one with spades inside. All the diagrams show only that the striped wires go to 3 of the 4 posts on the switch, as you said. Interestingly, some of the UK cars did not use the Blue/Green wire. My Prefect switch only has 3 posts, 2 on and 1 common, center position off.

 A Jaguar friend says the motor looks about like his '76 XJ. It has 2 speeds plus you pull the switch out and it parks the blade off the windscreen. Could this be the answer? I didn't thinkg the Spridgets were that sophisticated. I'm afraid my own '67 Sprite is still a long term project. Anyway, is it safe for me to ground the black wire and individually apply 12 volts to the striped wires and see what happens? Or does that run the risk of losing the smoke? If it does work like the Jag then that would be really nice as I need to get the blades fully off the windscreen as it opens at the bottom.

 

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

enf,

I doubt you will have the park off the screen function on that motor. Go ahead and hook it up as you describe and try out the various combinations. Unless you hook the solid green wire to constant power it won't park. Rather, wherever the thing is in its stroke, it will stop moving when you disconnect from whichever power wire you are using. Try it this way. I think you'll find that wherever it stops, energizing the green wire will make it run briefly, until it reaches the park position. Actually, one of the other wires is used in the parking function as well. It is the "stall" wire.

The switch logic for the way all this works with five wires for two speeds is somewhat convoluted, and frankly, I just don't have the time to type out the pages for it. Suffice it to say that if you want it all to work correctly you will need a Sprite/Midget late style switch and an appropriate wiring diagram. If you wire it all up the way it shows it will work as advertized. I hope the sweep and park positioning are compatible with the vehicle on which you intend to install it.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Thanks again Bill. I'll go ahead and try testing it then. I was pretty confident of the function of the green and black wires. Also, late last night I found an article on the web (http://www.geocities.com/sprite-midget/wipers.htm) that also helped when compared to the diagrams I do have. I now feel pretty confident about the blue/green and the red/green wires. But I'm still puzzled as to the need for the brown/green since the plain green should handle parking. Oh well, off to begin experimenting.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

en,

The brown/green causes the motor, when switched off, and then parked by the green, which then deenergises itself with the cam switch, to become a generator which shorts itself, thereby becoming a dynamic brake. That's why I called it the stall wire. It's so the system doesn't coast along and mispark the blades partway back up the windscreen, and also so that it doesn't go past the parking switch cam and start the whole parking process again, and again, and again...

See, I told you it was convoluted. If you would like to see a diagram of the whole thing, get hold of a TR6 factory manual (or reprint) and go to the electrical section. Even after staring at it a while you'll be saying HUH? til it all suddenly dawns on you. The reason it came to me was that I've been into slot cars since I was a lad, and that's what they use for brakes. It's called regenerative braking, or dynamic braking. Diesel locomotives, which are better called diesel/electric locomotives (really a kind of hybrid) use this same principle to slow down without wearing out the brake shoes on all the cars and themselves. If you ever get to look down on one from a bridge you'll see a whole series of fans on the roof. In addition to cooling the engine(referred to as the prime mover) these fans cool the resistor banks which is where the current from the wheel motors is converted to heat given off to atmosphere when those wheel motors are turned into generators to help arrest the momentum of the train during braking. Jeez, I can go on...

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Well, that explains it then. As soon as you said dynamic brake, I knew where you were going. Railfan and model railroading are way back there in my past somewhere. Makes perfect sense now, in a Lucas frame of reference, of course. I'm sorry to be a pest but I do thank you for taking your valuable time with the explanation. I'm glad you didn't have to type the several pages suggested above ;-)

 I'll go on and try to make it work without that stall wire then just using my car's on-off-on toggle switch. As for the sweep and park being compatible, it's really not a big problem. My wipers are lever actuated. I'll make a mounting bracket an let the Lucas cable drive the levers. I may have to make a new lever arm to get the sweep right but that's pretty simple. I also have a backup manual mechanical plan for the off-screen park. Not particularly simple but then I don't expect to get caught in the rain often in a 60 year old car either.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)