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I've stripped down most of the wiper motor gearbox to remove the old congealed grease and clean the parts. Only part left to try to remove is the helical shaft from the motor, there's a nut and screw slot on the casing at the shaft end - wondering what this is? Will undoing this allow the shaft to be removed or will this only be possible at the motor end? Can't upload a photo - get message ! - 200.

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Here is a pic of the wiper motor assy on a TR5 which is same as TR4A

https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/electrical-system/wipers-washers/windscreen-wiper-system-tr5-6.html

The scrolled bit is part of the armature which is removable as an assembly.  Undo the two slotted screws at the brushes end of the motor and the fields and armature can be removed as an assy.  The slotted screw you are seeing at the gearbox end sets the armature end float.

Cheers

Peter W

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13 hours ago, BlueTR3A-5EKT said:

Here is a pic of the wiper motor assy on a TR5 which is same as TR4A

https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/electrical-system/wipers-washers/windscreen-wiper-system-tr5-6.html

The scrolled bit is part of the armature which is removable as an assembly.  Undo the two slotted screws at the brushes end of the motor and the fields and armature can be removed as an assy.  The slotted screw you are seeing at the gearbox end sets the armature end float.

Cheers

Peter W

Thanks Peter, I had an idea that it might be something to do with shaft adjustment. As scroll and wheel seem to mesh ok, I'll leave alone.

Cheers,

Roger

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I've rebuilt 200 of these.  Here are some warnings, advice, opinion etc

1. leave the end float screw in place.  There are several different types and some come out easily others less so.

2. check armature for signs of overheating, "black wire".  I can rewind these.

3. check soldering of wires to commutator.  I've seen where the factory missed a joint and it ran for years, until I cleaned it!

4. If you have a worn commutator I have spare ones or can get on eBay if you know what to look for

5. look for wear leading to wobble in the Oilite bearing that carries the main gear. This increases the backlash at the blade tip.

6. small easily lost bits associated with the main gear are:  horse-shoe clip, rotating contact, thin washer between the crank-arm and the gear, conical washer under the main gear, flat washer and C-clip on the end of the gear shaft.

7. don't try to remove the self-aligning bearings for the armature.  Won't have any wear that matters.  Just make sure they are free to self-align.

8. the pole piece was bored inline and is NOT reversible. So mark it before you remove it.

9 the brass bush at the end of the crank-arm is usually worn out, again this adds to backlash at the blade tip.  These bushes DON'T float in the crank-arm. But you often find they have come loose.

10 if it's two-speed motor examine the resistance overwind. Usually suffer from damp.

 

 

 

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10 hours ago, AlanT said:

I've rebuilt 200 of these.  Here are some warnings, advice, opinion etc

1. leave the end float screw in place.  There are several different types and some come out easily others less so.

2. check armature for signs of overheating, "black wire".  I can rewind these.

3. check soldering of wires to commutator.  I've seen where the factory missed a joint and it ran for years, until I cleaned it!

4. If you have a worn commutator I have spare ones or can get on eBay if you know what to look for

5. look for wear leading to wobble in the Oilite bearing that carries the main gear. This increases the backlash at the blade tip.

6. small easily lost bits associated with the main gear are:  horse-shoe clip, rotating contact, thin washer between the crank-arm and the gear, conical washer under the main gear, flat washer and C-clip on the end of the gear shaft.

7. don't try to remove the self-aligning bearings for the armature.  Won't have any wear that matters.  Just make sure they are free to self-align.

8. the pole piece was bored inline and is NOT reversible. So mark it before you remove it.

9 the brass bush at the end of the crank-arm is usually worn out, again this adds to backlash at the blade tip.  These bushes DON'T float in the crank-arm. But you often find they have come loose.

10 if it's two-speed motor examine the resistance overwind. Usually suffer from damp.

 

 

 

Thanks Alan, good tips! I seem to have got it going - although only at one speed.

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Photos of coil wiring and switch connections.

Note that I am using PTFE covered wire (blue) for the overwind.

For slow you ground RED and BROWN.   For FAST you only ground RED.

You always ground RED to run because, as you see in the photo, this feeds the brushes.  BROWN just shorts out the overwind.

It's easy to get a short from the BROWN wire tag to the long-bolt.  I use plastic straws to insulate the long bolts.

 

coil2speed-1.jpg

34477-3.jpg

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On 8/18/2019 at 10:25 AM, AlanT said:

Do you want to fix it?

You want a resistance of about 10 Ohms.

My usual supplier:

www.wires.co.uk

01371 238013

Unit 3 Zone A, Great Dunmow, Essex, CM6 1HD

has a website problem at present.

Thanks. yes will go for this.

Edited by rogerowen
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To speed up the motor you need to reduce the effect of the field winding. Two ways of doing this, 

Use a series resistor to decrease the current through the winding. The resistor will get warm as it is dissapating energy.

Add extra wire to the winding, but in a reverse direction to decrease the magnetic effect of the coils.

Wire is cheaper than a resistor, & easier to locate.

Bob.

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No, the fast overwind has nowhere near enough turns to have any effect on the magnetism.  There are 700 turns on the main winding and about 10 in the original overwind.  You can take 50 turns off the field and there is negligible change in speed or torque.

It works just like a 10 Ohm resistor because it is in effect a wire-wound resistor.  Winding round the field-coil is just an easy place to store the wire.

I've mounted wire-wound resistors in the space next to the crank-arm. The problem is getting the connection up to the brush-arm area.  You have to drill holes to do this, so the wire does not get caught by the gear!  Photos show this.

The wire I use, for the overwind, is PTFE covered Nichrome.  It's the 0.45mm Nichrome wire that you need. 

This is hard to solder and I always make a "mechanical joint" like in a 1950's wireless set.  If you scrape this wire in an attempt to improve solderability you find that the opposite happens.  This wire has some coating to improve solderability and you'll remove it!

You can wind 7 or 8 turns,  the 8 turns is near the original factory spec but I tend to do 7 turns because this gives a bit more torque, for not much reduction in speed.  If you wound 10 turns, it probably won't start in FAST and stalling is to be AVOIDED on these motors, as it burns the armature.

 

 

 

 

2speed-mod-4.jpg

2speed-mod-2.jpg

Edited by AlanT
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Oh I'll try that.  I use 85% Phosphoric for metal cleaning.

Photos show a FAST overwind that I found in a motor that had been "restored professionally" possibly in the USA.

Well it did actually work but somehow mine look better.  No original cotton insulation left so wrapped in layers of sticky tape. Must have been a fiddle to do this.

field-notme-1.jpg

field-notme-2.jpg

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