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Overdrive solenoid - fuse question

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kch

kch

Senior Member
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I have now burnt up my old overdrive solenoid. But I also found out that the wires to to the solenoid looks burnt. Before I replace the old solenoid, I thought it was an idea to put a fuse on the wire to the solenoid because there is only two fuses on the whole electrical system of the Healey.
1. Have anyone put additional fuses on their Healey ?
2. Does anyone know know how many amps an additional fuse to the overdrive solenoid should be ?
 
Hello Kch,
I seem to remeber that the solenoid draws about 20 amps initially on switch on. There are two windings in the solenoid, a strong pull in and a much weaker hold in coil. There is an internal switch in the coil which cuts out the pull in winding when the solenoid is fully engaged. It is advisable to ensure that the solenoid is correctly adjusted and that it is not drawing more than about one amp when fully engaged or you will burn out the new solenoid also.

Alec
 
I agree with Alec. I have added an inline 20 amp fuse to this circuit just in case the internal switch fails to open. Probably overkill, but adjusting the internal switch contact (under the rubber cover on the top of the solenoid) is much cheaper than replacing the solenoid.

As Alec said, verify that the contact is opening. The solenoid arm should be adjusted to allow full bottoming/pull.

Adjusting the solenoid stroke/lever position can get somewhat complicated on an old transmission. The standard shop manual method, frequently is not optimum. But that is another subject. We can go into it if you wish.
D
 
HI Piman that is correct.However, if you add a A fuse to the circuit it will require A fault current which is 200% of the selected fuses rating to Interrupt the circuit within a 5 sec time interval.Similarly, for a given standard AG fuse they are designed to carry a 110 % overload for a Maximum period of 4 Hours,and 135% overload for a maximum period of 1 hour.Therfore, IMOP a 10ampere fuse is more than adequate to handle this circut.---Fwiw---Keoke
 
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Hello Keoke,
I did not advise a fuse rating, merely an estimate of the load.

Alec

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Just completing the circuit ole chap--- /ubbthreads/images/graemlins/cheers.gif Keoke /ubbthreads/images/graemlins/laugh.gif
 
[ QUOTE ]
HI Piman that is correct.However, if you add a A fuse to the circuit it will require A fault current which is 200% of the selected fuses rating to Interrupt the circuit within a 5 sec time interval.Similarly, for a given standard AG fuse they are designed to carry a 110 % overload for a Maximum period of 4 Hours,and 135% overload for a maximum period of 1 hour.Therfore, IMOP a 10ampere fuse is more than adequate to handle this circut.---Fwiw---Keoke

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Thanks for the answers. Have you put any other fuses on your Healey ? And if ?, where ? amps ?
 
Yes KCH, But I also use relays to switch all hi current lighting-"Head/Driving lamps. Headlamps are fused.Driving lights are fused,Overdrive is fused Tail light circuits are fused , Fuel Pump is fused and the tail Numbers Lamp is also fused
My driving lights are operated by a common switch Formerly"Panel Lights" only in the full down position and operate independant of the head lamps.The original single position "panel Light switch" has been replaced with a standard "Head Light switch.All of the fuses are sized based on 1&1/2 times the steady state load current of its circuit. I hope this helps you a bit--Keoke
I forgot to mention that all my 12 Volt power is obtained at the starter solenoid and includes a 25A circuit breaker.
 
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