Lotus Elan

Engine Cooling Fan Wiring

PostPost by: Gazzerb » Wed Jan 25, 2017 9:01 pm

I know this should be straight forward but here goes.
My late +2 S130 arrived with just remnants of the original wiring loom, having been cut up by the PO.
With a new loom bought from Chris Neil quite a few years ago, I am trying to sort out a few of the discrepancies.

The Lotus wiring diagram shows three wires to the cooling fan motor; yellow/green, black/green and a black earth.

The old loom has the remains of these three wires at the correct location. A stud on the fan motor has an extra nut where possibly the earth wire ring connector was attached.


However, the new loom and its diagram does not have an earth and I cannot understand why it should have one.
Can anyone please confirm their wiring arrangement for the fan motor with or without the earth.

Thanks
Gary
Attachments
Wiring Diag Extract.pdf
Lotus wiring diagram extract showing fan
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Gary

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PostPost by: Hawksfield » Wed Jan 25, 2017 10:01 pm

Hi

Here is a drawing of the wiring for a +2 s 130

Shows one feed and an earth
Attachments
wiring-diag.jpg and
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John

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PostPost by: pharriso » Wed Jan 25, 2017 10:07 pm

Hi Gary, I recently acquired a Plus2S 130 radiator cooling fan for my Sprint & noticed the extra earthing connection on the motor case.

"Can anyone please confirm their wiring arrangement for the fan motor with or without the earth."

Don't worry about that extra earth to the motor case, it is not required. Not sure why it was added to the Plus2S 130 wiring! The motor works fine with just 2 connections.

p.s. The original Lotus wiring puts full motor current through the Otter switch thereby shortening it's life. If you take a look at my thread here http://www.lotuselan.net/forums/lotus-electrical-f38/sprint-electric-cooling-fan-wiring-t38473.html I have provided a wiring diagram adding a relay to switch power to the motor.
Phil Harrison
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PostPost by: p.faurie » Thu Jan 26, 2017 8:29 am

Hi Gary,
Not 100% on this but on my early S130 the one with the same wiring as an S , I think that earth fixing could be for the bonnet. (Hood) lamp, as the wiring for it is running along the steel tube at the front of the bonnet and terminates by the fan.
Phil
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PostPost by: billwill » Thu Jan 26, 2017 3:44 pm

All metal parts should have a connection to earth/chassis; it helps reduce radio interference.
Bill Williams

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PostPost by: pharriso » Thu Jan 26, 2017 4:35 pm

p.faurie wrote:Hi Gary,
Not 100% on this but on my early S130 the one with the same wiring as an S , I think that earth fixing could be for the bonnet. (Hood) lamp, as the wiring for it is running along the steel tube at the front of the bonnet and terminates by the fan.
Phil


The Federal S130 wiring diagram shows that 3rd wire (extra earth to the case).
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PostPost by: Gazzerb » Thu Jan 26, 2017 9:35 pm

Thanks all for your help.
Whilst clearly the motor will run fine with just the two connections, I think Bill is right about the earth providing a reduction in radio interference.
At least I know now........probably!

Gary
Gary

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PostPost by: Craven » Thu Jan 26, 2017 11:04 pm

Hi.
Those interested in a reason for the earth or chassis connection of the motor body, fan motor, window motors and wiper motor as it?s not part of the electric circuit may like to ?search?
Faraday Cage.
FWIW
Ron.
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