Reversing switch or contactor?

[jdunmyer]

Why would one want a reversing switch rather than a contactor? When building up my 1979 CC with a Curtis 1205 controller, I found a reversing contactor from an electric pallet jack. As those seem to be equipped with 400-amp controllers, the reversing contactor must be rated at that, right? The only problem that I saw was the coil on the contactor was 24 volts. A bit of measurement and calculation told me that a 15 ohm power resistor would take care of that issue.

It works great, I have an Allen-Bradley 3-position selector switch on the dash instead of the big ol' selector. Other than the 900 ma extra draw, why would I NOT want the contactor?

[simple man]

Originally Posted by jdunmyer

Why would one want a reversing switch rather than a contactor? When building up my 1979 CC with a Curtis 1205 controller, I found a reversing contactor from an electric pallet jack. As those seem to be equipped with 400-amp controllers, the reversing contactor must be rated at that, right? The only problem that I saw was the coil on the contactor was 24 volts. A bit of measurement and calculation told me that a 15 ohm power resistor would take care of that issue.

It works great, I have an Allen-Bradley 3-position selector switch on the dash instead of the big ol' selector. Other than the 900 ma extra draw, why would I NOT want the contactor?

It's a great idea, but all of us don't have access to used ones and new ones are out of reach to some of us.

[jdunmyer]

SM,
That makes sense. Of course, it's nice to know that you CAN use the contactor from an old pallet truck. I've seen those things around here and there and never thought of the contactor until recently.

[simple man]

Originally Posted by jdunmyer

SM,
That makes sense. Of course, it's nice to know that you CAN use the contactor from an old pallet truck. I've seen those things around here and there and never thought of the contactor until recently.

Believe me, if I run across one I'll definitely grab it! My F-R switch is mounted up front at my knee, so you can see how much heavy cable I could save having a reversing contactor near the controller! I considered this when I was figuring out the cost of upgrading the high current cables. I will need almost 25' of cable just for the F-R switch, if I leave it where it is now! I'm going to start my upgrade with new cables as everything else will depend on them! Thanks for mentioning the contactor, because it is a good idea, even though expensive.

[jdunmyer]

I first tried my pallet truck contactor on 24 volts and measured the current draw, it was just under 900 Ma. Ohm's Law tells me that I need a resistor of about 15 ohms and it has to handle 10 or 12 watts of power. A quick search turned up power resistors on Amazon, a 15 ohm, 25-watt resistor was less than $4.00, so I ordered 2. Took a couple of weeks, but they arrived, and NO shipping charges.

Disclosure: I have no connection to Amazon other than being an occasional customer.

The resistor is wired in series with the common connection on the contactor coils, so 1 resistor serves both coils. All the wiring on my cart has been done by using the diagrams in the Curtis 1204/1205 manual.

BTW: I've found a couple of electric pallet trucks in the scrapyard, and SOME have a Curtis controller rated at 24-36 volts, so will work in a 36-volt golf cart. You'll still need the speed control pot, of course. If you're wanting to change an old resistor cart to a controller, it's a cheap way to go. Also, some of the pallet trucks use very heavy cables, so grab them while you're at it.