contactor - (El Chopper ET/Etek Motor)

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tercero
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contactor - (El Chopper ET/Etek Motor)

I'm wondering how exactly this works. What does a contactor do? What's the advantage? I'm building a new project built around a Mars motor and Sevcon controller.

T.

Stleride
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Re: contactor - (El Chopper ET/Etek Motor)

`tercero,
Welcome to our V is for Voltage Community, can you give us some more details about your project?

Stleride
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`

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Stleride
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Re: contactor - (El Chopper ET/Etek Motor)

` :?
Which Mars motor are you using?

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tercero
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Re: contactor - (El Chopper ET/Etek Motor)

The motor is a ME0201013001 rated for 36V max, the controller is a Sevcon SC1 180A.

How did I break that?

Stleride
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Re: contactor - (El Chopper ET/Etek Motor)

` :?
OK, is the project a secret, if we knew what it was we could probably move this to a better Forum where you would get more replies.
There are so many Subjects listed, and just the word "contactor" just doesn't catch a lot of attention.

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rgx
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Re: contactor - (El Chopper ET/Etek Motor)

Tercero,

I'll try to answer the question anyway. A contactor is little more than a heavy-duty relay. In EVs, a contactor is used primarily for safety reasons, and only for DC motor setups. A DC controller has one dangerous fault mode, that one of the output FETs is short-circuited. If that happens, the motor will be at full throttle and nothing can stop it. So that's why many DC setups include a contactor to cut off power, between the motor and controller, or between the battery and controller. The contactor can be activated by a safety switch, or by the brake switch. (It could get dangerous anyway, because the user might not be quick enough to reach for the brake or safety switch when the fault occurs.)

A brushless DC or AC motor setup does not have this fault mode, so no contactor is needed for those. If a FET is short circuited, the motor only stalls.

Finally, in some DC motor setups, a contactor is used to switch the motor between serial and shunt mode, to improve low-end torque at take-off and maintain performance at higher speeds.

Best regards,
Rolf

Stleride
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Re: contactor - (El Chopper ET/Etek Motor)

` :?
Sorry I wasn't clear, what are you trying to build? What is the finish product of your Project, or is this just a experiment or something. Either way we want to do everything to guide you to the correct location or person that can answer your question. We even have several Fileshares we're holding until we learn more about your Project. We also can't locate any specs on a Mars ME0201013001, what page is it on in the Mars Motor Catalog
FWIW, I was a Aircraft Electrician in the Air Force, so I'm very familiar with relays etc.

Stleride
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andrew
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Re: contactor - (El Chopper ET/Etek Motor)

The main purpose for a contactor is to make the final connection from your batteries to your controller, effectively energizing the vehicle.

A contactor can be energized by a microswitch integrated into the throttle. That way the high energy system is not energized until the moment you actuate the throttle, which is a really good safety feature. A contactor is designed for repeated frequent use. It can and is meant to switch live current.

A contactor can also break high current, but should not be relied on for this purpose. Note that a contactor DOES NOT substitute a safety disconnect or a fuse!

I see it as an additional safety feature. Lets say you have x EV with no contactor, a high amp fuse and a large disconnect. You miswire it and switch on the large disconnect, causing the disconnect to arc, and catch fire. The short is not enough to cause the fuse to blow. Now you have no way to stop a potential explosion without actuating a disconnect that is on fire and melting. Its good to have a way to remotely disconnect a system, e.g., by not touching the high-power disconnect. A contactor is exactly this, and it works well in conjunction with a manual disconnect, and a fuse, but does not replace them because contactors can usually not break as much current as a manual disconnect (such as a circuit breaker).

---
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My KZ750 Project: here

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
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tercero
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Re: contactor - (El Chopper ET/Etek Motor)

Thanks all. I wasn't trying to be evasive (or rude), I was just unsure what part a contactor played. I built an El Chopper ET a couple of years ago (back when visforvoltage was under different management??) and most of the time Fechter used to answer all my inane questions. I didn't use a contactor at that time, the plans didn't call for one, but now that I have a brushless etek (type) motor, purchased directly from John Fiorenza (Mars Electric LLC) and was looking into building a new bike, I wanted to know the advantages (or disadvantages) or including one. I found info on the White-Rodgers type 586 contactor that I'll use then.

Thanks for the information.

Tecero ;)

How did I break that?

davidchristiansen
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Re: contactor - (El Chopper ET/Etek Motor)

microdc
I assume the MARS motor you mention is the DC 'pancake' type used with a controller, (Sevcon) or the like?
I wonder where you buy that motor? I'v searched on the web and only found a telephone nbr to who know's. My intention is to use the motor in a sailboat. Thks in advance.

microdc

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