2 speed wiper upgrader on a TR4

[MRG1965]

Hi all, I’m starting to think about another one of my winter projects to upgrade the single speed wipers on my TR4 to a two speed motor.

I have sourced a two speed pull switch to replace the existing and have also sourced a DR3 two speed motor (from a Jaguar I understand). I’ve used the multimeter to see which terminals are connected when.

The issue I have is that looking at various threads both on this forum and on the web it appears that connecting up the motor is not as obvious as one might think, and appears to be the opposite in some cases, and burning out motor and releasing the Lucas smoke is all too easy and expensive to reverse.

I’ve used a multi meter and had the motor apart and all looks okay, the only issue I can see is that the odd shaped reciprocating arm in the head sticks when the pin on the wheel is in line with the slot the mechanism slides up and down in, I’ve had it apart and it all looks ok and is free without the C clip and retaining spring, but I’ll put the wheel from the existing motor in any way.

 

The car is converted to negative earth and the DR3 has 6 wires, inc the auto part wire.

1 – Green – Left commutator brush

2 – Red/Green – Right Commutator brush

3 – Yellow/Green – 10 Ohm speed coil (wrapped around main armature winding)

4 – Purple/Green – 10 Ohm speed winding and the main armature winding

5 – White/Green – Main Armature winding

6 – Red – Park switch (single closed/open version, no regenerative braking)

The problem I have is not knowing what wires to connect to what to make the unit work correctly, so if there is anybody out there with a wiring diagram or advise, I’d be much appreciative.

Tried to upload a picture, but won't upload.

 

Regards

Mark

 

 

TR4 Negative earth

DR3 75803A

Edited November 9, 2015 by MRG1965

[littlejim]

^{this is the best I can do:}

 

^{The unusual bit is the self parking bit , the wiper is live when you turn it off.}

^{The motor keeps going until the blank segment on the disk is under the wiper motor contact.}

Edited November 9, 2015 by littlejim

[MRG1965]

Thanks Littlejim, unfortunately, mine has 6 wires and a slightly different set-up on the park switch.

I've drawn a small diagram of how it is wired internally and managed to upload the photo of the internals (minus the park switch)

 

 

Mark

[peejay4A]

Mark

As it's from a Jaguar the TR4A wiring arrangement won't help. I suggest you seek out a Jaguar wiring diagram and adapt it for the TR.

Edited November 9, 2015 by peejay4A

[Grahamgl]

Mark,

You could try contacting Steve Hunt,steve@stevehunt.demon.co.uk,(01217770071),he rebuilds Lucas wiper motors. He sells units on ebay (Tankard03). He rebuilt a DR3A for me, nice chap.

You could also PM Alant on this forum, he seems to be the forum expert.

Check the sweep angle on the plastic wheel is 120 degrees.

Graham

[stuart]

As stated you do need a Jaguar wiring diagram, Ian C has the same type of motor on 4VC FWIW.

Stuart.

[ianc]

If you are lucky (!), attached will be a diagram of 4VC's 2-speed wiper motor connections, which I drew in 1994.

You will need the correct type of rotary switch (PRS7) to make this work - probably to be found on a Jaguar, I believe.

Be aware that when the motor is turned off, the wiper blades are driven hard to the right (farther than the sweep when wiping the screen).

Ian Cornish

[MRG1965]

Hi guys, I have the Jag diagram, but unfortunately it only shows the Jag switch, and I'd need to find its switch to work out which terminals connected to what to work out the wiring. I'll pm the names mentioned to see if there is any further help, many thanks.

 

Mark

[Don H.]

Ian, here's a copy of your diagram hosted in my SmugMug archive, so it won't get lost if you have to clear out your upload space at some point. Click on the image for the full size.

 

[MRG1965]

If you are lucky (!), attached will be a diagram of 4VC's 2-speed wiper motor connections, which I drew in 1994.

You will need the correct type of rotary switch (PRS7) to make this work - probably to be found on a Jaguar, I believe.

Be aware that when the motor is turned off, the wiper blades are driven hard to the right (farther than the sweep when wiping the screen).

Ian Cornish

Cheers Ian yes thats the type of rotary switch the jag diagram has, but now I have the internal switch connections I can workout the wiring, hopefully without frying it.

 

Many thanks

Mark

[ianc]

Just to clarify, I have used the standard Electrical Engineering convention that if wires in the diagram cross (X), they are NOT connected.

If they meet at a T, they are connected.

The linking occurring inside the switch itself is described in Switch Operations to the right of the diagram.

The linking of terminals on the outside of the switch is as shown (e.g. 1-4-12). I cannot be certain that all these external links are strictly necessary, but they are there, and I have never bothered to work out what might occur were any to be removed!

 

DonH - it's clever the way that that you have made the diagram increase in size if clicked. Thank you!

 

Ian Cornish

[MRG1965]

Just to clarify, I have used the standard Electrical Engineering convention that if wires in the diagram cross (X), they are NOT connected.

If they meet at a T, they are connected.

The linking occurring inside the switch itself is described in Switch Operations to the right of the diagram.

The linking of terminals on the outside of the switch is as shown (e.g. 1-4-12). I cannot be certain that all these external links are strictly necessary, but they are there, and I have never bothered to work out what might occur were any to be removed!

 

DonH - it's clever the way that that you have made the diagram increase in size if clicked. Thank you!

 

Ian Cornish

Thanks for the clarification Ian.

Plan is to use a small value fused link, large enough for the motor to operate, but not short and damage, and then work my way through the wiring, hopefully this will save me from frying the innards, if I inadvertently make a dodgy connection.

I'll start by wiring up the normal speed circuit, as it is in the single speed motor and then go from their, if it is still working.

 

Mark

[BlueTR3A-5EKT]

Does the propsed wiper motor have a park sw on the round cap or is it like the unit in 4VC, having a side of the gearbox limit switch?

Does it have - A one piece aluminium or two piece steel gearbox lid?

If it is like the unit on 4VC and you want the thing to self park I suspect you will need the correct type of wiper rack that has the projecting switch contact finger - something that standard TR wiper racks do not have.

 

Image of what you may be needing if you are missing it.

http://www.introcar.co.uk/rolls-royce-bentley-models-1956-1965-c79/electrical-ignition-c32475/wiper-blades-arms-motors-washers-c32502/rolls-royce-silver-cloud-i-bentley-s1-c32503/wiper-rack-cut-to-fit-pp255035

 

Cheers

Peter W

[AlanT]

Sorry I missed this earlier.

 

If it's from a Jaguar this will have all 6-wires coming out so that it can do reverse parking.

 

You will to rewire this to use ordinary switching.

 

These are actually quite valuable to Jaguar owners so I suggest you sell it as is and get the right one.

 

Post a picture and I'll tell you more about it.

 

I forgot to add that I can converts ANY single speed Lucas motor to 2-speed operation.

 

Also I keep a small stock of wiper motors for all TRs except TR6.

Edited November 24, 2015 by AlanT

[AlanT]

Just in case anybody gets tempted to fit a Jaguar wiper-motor I'm posting this to show what you will be dealing with.

 

It might also interest Mr Pringle who has the same thing on his Snipe.

 

These have "reverse parking" and a switch to suit:

 

 

So the motor has 6-wires also:

 

 

The crank has an eccentric-cam to make it grow longer, when the motor drives backwards:

 

 

 

These cams add some friction and are prone to wearing loose. This makes the blades go floppy.

Edited December 5, 2015 by AlanT

[ianc]

AlanT - although I stripped 4VC's wiper motor some 20 years ago, washed out all the hardened grease, fitted new brushes and filled with new grease, I never investigated how the reverse parking was achieved. Thanks very much for the explanation and the warning about wear in the eccentric leading to floppiness!

If there is floppiness (slop/backlash) in the eccentric, can anything be done to improve matters?

Ian Cornish

[AlanT]

Remanufactured cams are available.

I have some of these motors in servicable condition.

They are all fixable.

 

The benefit of a "reverse parker" is that you can have the sweep in a more useful part of the screen

and then they can put themselves away at the bottom of the screen.

 

The down-side is the special switch. I've thought about doing a relay board so you could use a normal switch.

But these "reverse-parkers" are hard to find.

[TR 2100]

Alan,

 

You have solved a long-standing mystery.

 

I acquired a 2-speed wiper motor and switch in my TR3 days.

Never got it fitted, so it went into the TR4 when I had it restored.

 

I gave the garage the switch - they said it was not suitable and

fitted the more normal 2-step headlight type pull switch.

 

It was one of the switches you show above, so now I understand

why the garage fitted a different one and returned my switch.

 

AlanR

[stuart]

MK2 and S type Jaguars had the same type of wiper motor and they had a standard Lucas lever type switch with two positions rather than that rotary cam one which is actually MK8/9 XK150 and MK1 type.

Stuart,

[AlanT]

What's happening here is that in the "off" or "park" position the motor rotates in the opposite direction

until the self-parker runs off the brass-conatct.

 

It does this because the field-coil connections get reversed.

This produces a lot of extra wiring and contacts, all of which degrade reliablity.

 

The motor in the photo is from an S-type Jaguar. It has an unusual fault.

I'll expalin this because the same fault could beset any kind of motor.

 

There is an early kind of gear that looks at first sight to be superior to later ones.

It has a riveted construction and a reinforcing plate on the underside.

 

Plastic is not very dimensionally stable. Moisture and pressure cause it to expand.

The gear in the photo now runs as a very tight fit on the armature spindle.

The motor runs OK but uses more current.

 

Being tight like this it will stall more easily on a dryish screen.

Be really hard to guess why this is happening if you don't know these motors well.

 

This is one reason why checking the running current is one of the things I always do.