Solenoid Continuity Question Please

[ThreeCW]

May the force be with you

[BobBoyce]

Originally Posted by Sergio

Both of those solenoids are bad, the 0L on the meter means Open Line.

Make sure You have not tried testing those 48v Solenoids by applying the Full pack voltage +72v directly to the coils, that would definitely burn them.

Actually, OL means Over Limit... In the case of continuity testers, it means that the resistance is higher than the highest ohmage of the range of the test. Typically that is 200 ohms on a simple continuity test. Any brand new fully functional 48V solenoid with an approximately 330 ohm coil will read as OL on a 200 ohm range continuity test. That does not mean the solenoid coil is bad, it means that it is beyond the range limit of the test being performed. Ignoring this advice will result in wasting money going through multiple new solenoids trying to find one that passes a continuity test! A simple fact is that 48 volt solenoids MUST have a higher impedance coil in order to limit current flow, or it will burn out the coil! A 12V solenoid will pass a continuity test because it has an impedance of under 100 ohms. Most 24V solenoids will also pass a continuity test because most will be under 200 ohms. A 36V or higher solenoid will not pass a continuity test at 200 ohms. E = I * R where E is voltage, I is amperage, and R is resistance. Voltage is not what causes a solenoid to close, it's the current flow through the coil that does it. The impedance (resistance) of the coil is what determines the desired current at the rated voltage. I'm not wanting to be so technical here, but it's obvious that there is confusion here.

[Sergio]

Originally Posted by BobBoyce

Actually, OL means Over Limit... In the case of continuity testers, it means that the resistance is higher than the highest ohmage of the range of the test. Typically that is 200 ohms on a simple continuity test. Any brand new fully functional 48V solenoid with an approximately 330 ohm coil will read as OL on a 200 ohm range continuity test. That does not mean the solenoid coil is bad, it means that is is beyond the range limit of the test being performed. Ignoring this advice will result in wasting money going through multiple new solenoids trying to find one that passes a continuity test! A simple fact is that 48 volt solenoids MUST have a higher impedance coil in order to limit current flow, or it will burn out the coil! A 12V solenoid will pass a continuity test because it has an impedance of under 100 ohms. Most 24V solenoids will also pass a continuity test because most will be under 200 ohms. A 36V or higher solenoid will not pass a continuity test at 200 ohms. E = I * R where E is voltage, I is amperage, and R is resistance. Voltage is not what causes a solenoid to close, it's the current flow through the coil that does it. The impedance (resistance) of the coil is what determines the desired current at the rated voltage. I'm not wanting to be so technical here, but it's obvious that there is confusion here.

If You look closely at his meter screen he was not doing a continuity test, but an auto range resistance test in kΩ.

I do agree continuity tests are not a good way to test any device unless you are familiar with the characteristics of both.

[BobBoyce]

You may be able to read those tiny images that well, I cannot. My screen is only 10" on this Dell Mini10 netbook. I could see the OL but not the smaller details. I choose to live off-grid so no high powered computers or large monitors are employed here for my limited internet usage.

[radioman]

To add to the confusion what is needed here is conductance between the two small solenoid post. The unit of conductance is the Mho (G). The only way to get the conductance is first measure the resistance in ohms (R) and divide the ohm reading into one (G=1/R). A good coil in a typical golf cart solenoid would have approximately .0025 Mhos. (R=1/G)

[yurtle]

Why not just power up the coil with the proper voltage, then do a continuity test on the large posts?

[radioman]

Originally Posted by yurtle

Why not just power up the coil with the proper voltage, then do a continuity test on the large posts?

That would be too simple.

[cgtech]

Originally Posted by yurtle

Why not just power up the coil with the proper voltage, then do a continuity test on the large posts?

Wait! Do what!? Without first explaining all the nerdy intricacies of the how's and why's? I think not, my friend!

[konakid]

Originally Posted by yurtle

Why not just power up the coil with the proper voltage, then do a continuity test on the large posts?

I already know the main contacts are not closing (error code from controller, and no sound). But I have no idea what voltage is supposed to be supplied to it. It looks as if it is 57v. So, it's not a typical setup - a 72v AC Cushman utility cart. And since both solenoids are exhibiting the same symptoms, it seemed as if something other than the solenoid might be at fault.

Since the circuits on this particular cart are more complex, and the controller appears to have some factory custom programming, we don't know why the main contacts remain open. http://www.buggiesgonewild.com/elect...39-please.html

The solenoid was buried in behind the controller which were both enclosed in a box, within another box, that required removing the electric dump bed, jacking the vehicle, and ripping out some riveted body cowling to get to. So, I didn't want to just replace it, if it was some other switch or connection. Your typical path and trouble shooting thinking is not working well in this situation.

So, I saw this You Tube video and thought if it was this simple to test the solenoid, then I could easily do that and get to the bottom of this problem. But, I guess it isn't quite this simple. https://www.youtube.com/watch?v=oYHzIDnU3Rw

Since I am a newbie with this stuff - here is another question. How does one go about supplying power to a solenoid (or other switches/parts) to test them. Is there a piece of equipment designed to supply various voltages in AC and DC to perform such testing. I assume there is - and then I probably need one if needing to work on carts.

[kgsc]

Hang in there kid.. I am assuming you have 12 volt batteries in this beast so to test your 48 volt solenoid you need 4 of those in series and 2 jumper wires. Start at either pack + or - and follow the series jumper wires to the 4th battery. That should get you 48 volts. Validate with your meter. Now take a jumper from each of the 2 posts that gave you 48 and put them on the small terminals of the solenoid you want to test. One to each post. You should hear/feel it click. If so, when power is applied there should be continuity between the large posts on the solenoid. If not its bad.