EzGo 2005 Clays Car does not operate

[Carts4you]

Originally Posted by Carts4you

JohnnieB I tested the system. We have a 1205 controller but it does not have a scanner port like some I have seen online. The reading between controller b- and m- is -.360 when solenoid activates and at full throttle drops to 0 volts. When letting go of pedal it goes up to reference voltage for a few seconds and then drops to roughly 17volts. Controller m- is connected to “A” stud on F/R switch. This cable looks good. I am thinking the problem may lay in the controller? I get reference voltage in all studs at motor when pressing pedal. The throttle readings are 1.6 at solenoid click and 2.6 at full throttle which is correct.

The only stud is "A" which does not have reference voltage but it is only connected to M-. So the voltages are the same as solenoid clicks, full pedal and when letting go. Does this make sense?

[JohnnieB]

Originally Posted by Carts4you

The only stud is "A" which does not have reference voltage but it is only connected to M-. So the voltages are the same as solenoid clicks, full pedal and when letting go. Does this make sense?

Yep, it makes sense.
The F/R switch is bad.

You have B+ on all the studs except the A stud, so there is an open between the A contact and either the B or the C contact via the contacts on the moveable cam.

Does the cart run in reverse?

Do you have a schematic for your cart that you can post? I haven't got one for a 1205 controller with A stud connected to M-.

[Carts4you]

Here you go. Can I test it? Also why would I get reference voltage in all four motor studs when depressing pedal? It does not run in reverse either.

[JohnnieB]

Originally Posted by Carts4you

Here you go. Can I test it? Also why would I get reference voltage in all four motor studs when depressing pedal?

Thanks.

You get voltage on all four motor studs because they are between the A stud and B+ at the battery pack. Start at the battery pack's main positive terminal and trace follow the thick black line through the solenoid contacts and motor windings and you'll see what I mean.

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If cart is wired the same as schematic shows, if you jumper A stud to the D stud, the cart should run, but only forward.

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Get a HD F/R assembly from Carts unlimited: http://www.cartsunlimited.net/f---r--switches.html

Or a Reversing Contactor: http://www.cartsunlimited.net/reversing-contactors.html

[Carts4you]

Thanks JohnnieB. I will trace back and jump the A to D stud. Will let you know.

[Carts4you]

Quick question JohnnieB....why would the car not run in reverse? Loss of circuit at A-D studs?

[JohnnieB]

Yes.

To get the motor to spin in the opposite direction for reverse, the amps going through the field (stator) windings are routed in the opposite direction by the F/R switch assembly.

Forward = A -> D & B -> C
Reverse = A -> C & B -> D

[Carts4you]

JohnnieB I jumped A & D and motor would activate! Replaced the F/R switch and car now runs perfect. The F/R switch had been replaced no more than 30 days. That is why I thought it could not be the problem. Is there any test on the switch itself to check if it works properly? What can cause the F/R switch to fail? Thanks for all your help!!

[yurtle]

Sorry if you mentioned it before, but you don't have your cart's setup in your sig.

I toasted mine by pushing it beyond its limits. I also melted two stock solenoids. Then I bought a ScottyB HD solenoid and FNR (F/R). Mine had apparently gotten a little loose, after years of use, and anytime you have a loose connection, I^2R kicks in, and it gets hot. Once the mechanical FNR gets too hot, the studs melt the plastic, which causes more resistance, which causes more heat...

My ScottyB mechanical FNR has worked fine for me, but a reversing contactor has no moving parts that can come loose over time.

As to checking/testing it, a wet finger can tell you if you have excess heat. This works on all battery interconnecting cables, motor terminals, solenoid, controller. An IR gun is safer, but what's the fun in being safe.

[JohnnieB]

Heat causes F/R switched to fail.

The non-moving contact gets hot and makes the plastic it is mounted in soft, then it can move physically and eventually no longer make contact with the opposing contact on the moveable cam.

I've never worked on a series cart, so I'm not all that familiar with installing and adjusting the F/R switch assembly, but I understand you have to make sure the lever rotates the cam all the way to the mechanical stops or the contacts won't line up completely, and the offset of the contact faces causes the current density to be much higher, which results in heat.

Also, the Heavy Duty F/R switch Scottyb (Carts Unlimited) sells is supposed to be the heaviest duty one around. Or going to a reversing contactor eliminates the contact misalignment issues.




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I see Yurtle beat me to it.