John Morrison Posted May 20, 2009 Report Share Posted May 20, 2009 Yet an other overdrive question I read that teh solenoid draws say 14 amps on throw in. and a couple of amps on holding. I have a standard multimeter that can raed 20 amps, but how do I go about connecting this, in other words what do I connect up to? to confirm correct operation of the solenoid? thanks john. Quote Link to post Share on other sites
Don Elliott Posted May 21, 2009 Report Share Posted May 21, 2009 John - Lets assume you have the solenoid in your hand. Hold it vertically. Use your little finger to gently support the central plunger. Connect the wire on the solenoid to a 12 volt car battery and touch the base of the body of the solenoid to the other battery post. The plunger will rise with a strong snap. This is the pulling amps. Some say it might be 15 amps or maybe 25 amps. But it only acts for a second. When the central plunger gets to the top of its travel inside the solenoid, the top of the plunger will open a contact (much like points) inside the top of the solenoid and the main coil will drop out of the circuit, leaving only the holding coil to retain the plunger up there. This takes only an amp or two. This is all you need to do to test your solenoid. Quote Link to post Share on other sites
ianc Posted May 21, 2009 Report Share Posted May 21, 2009 If you have a multimeter, it almost certainly can measure resistance as well as volts and amps. You can measure the resistance between the solenoid's flying lead and its casing, and it should be about one ohm. if you push the plunger into the solenoid, it should open the contact (as described by Don) and the resistance should increase to something like 12 ohms - both these figures are guessed, but they are of the right order (I can't be bothered to hunt out my spare solenoid to make the measurements). For more detail on the solenoid, see page D-49 of the Technicalities CD. Ian Cornish Quote Link to post Share on other sites
RogerH Posted May 21, 2009 Report Share Posted May 21, 2009 Hi John, with the solenoid connected to the car in the normal fashion, turn the ignition ON. Select 3rd or 4th gear - engine NOT running. Note the position of the ammeter needle (overdrive not engaged). Select O/D you should hear a loud click. The ammeter should jump momentarily. The ammeter needle should now show (just) a couple of amps - indicated by a slight move away from the position as note above. If no loud click then the inhibitor switches/relay/wiring is dicky. Roger Quote Link to post Share on other sites
stuart Posted May 22, 2009 Report Share Posted May 22, 2009 Hi John, with the solenoid connected to the car in the normal fashion, turn the ignition ON. Select 3rd or 4th gear - engine NOT running. Note the position of the ammeter needle (overdrive not engaged). Select O/D you should hear a loud click. The ammeter should jump momentarily. The ammeter needle should now show (just) a couple of amps - indicated by a slight move away from the position as note above. If no loud click then the inhibitor switches/relay/wiring is dicky. Roger Or if it is showing a large discharge then the pull in coil is still working and the solenoid needs the contact under the plastic cover adjusting. Stuart. Quote Link to post Share on other sites
Tr4Tony Posted May 22, 2009 Report Share Posted May 22, 2009 I believe that the od sol needs a 2 amp burst on actuation, then 0.2 amps continuous to hold the plunger in place ...... should be drawing 14 amps Regards Tony Quote Link to post Share on other sites
tthomson Posted May 23, 2009 Report Share Posted May 23, 2009 Hi John, Where the solenoid wire connects to the Gearbox loom, there is a bullet connector. Disconnect this and put the meter between the two wires, + to the loom, - to the solenoid. Switch on the O/D and see the current. However, because the pull in current is transitory, this will really only allow you to read the holding current. If you want to find the Pull in current then Ian's suggestion of measuring the resistance and then using Ohm's law, (V=IR), is best. TT Yet an other overdrive question I read that teh solenoid draws say 14 amps on throw in. and a couple of amps on holding. I have a standard multimeter that can raed 20 amps, but how do I go about connecting this, in other words what do I connect up to? to confirm correct operation of the solenoid? thanks john. Quote Link to post Share on other sites
John Morrison Posted May 24, 2009 Author Report Share Posted May 24, 2009 Just to say thanks for all the replies much appreciated, and I am off to 'Play' tomorrow. cheers, john. Quote Link to post Share on other sites
ianc Posted May 25, 2009 Report Share Posted May 25, 2009 Today, I made some measurements on a brand new, spare, overdrive solenoid which I bought from Moss some time ago. I think it is fair to assume that it was built to the same specification as the original Lucas item. Pull-in (Pull-in and Hold-in coils in parallel) 0.8 ohms, drawing about 15-17 amps. Hold-in (pull-in circuit disconnected by plunger operating the switch within the top of the solenoid) 12.5 ohms, drawing about 1 amp. For the technically-minded, this means that the Pull-in coil has a resistance of about 0.85 ohms, and takes about 14-16 amps. The current drawn will depend upon the state of charge of the battery, which is usually between 12-13.4 volts. Ian Cornish Quote Link to post Share on other sites
littlejim Posted May 25, 2009 Report Share Posted May 25, 2009 many thanks Ian. Should come in very handy when diagnosing O/D problems. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.