Anyone using a circuit breaker?

[Kevinator]

I'm thinking about trying this 30A circuit breaker from tncscooters.com. Should the fuse rating match the controller's continuous rating, or peak rating?

http://tncscooters.com/product.php?sku=101262

Anyone using one yet? How reliable are they?

 

[recumbent]

Yeah, I want to know this as well because they sell 40 amp breakers also.

My controler peaks at over 40 amps, but is rated at 35a.

 

[Kevinator]

My cyclone 900w controller is rated for 35A, but peaks at a little over 50A so theres a considerable gap in there. So would 35A be appropriate, or does it need a 50A breaker? I was planning to swap it out for a physically-smaller 30A controller but don't know what kinda current it will draw at peak.

 

[liveforphysics]

When sizeing a breaker, measure the peak load you see in normal operation, then divide by 0.8

Also, I would definately measure the currents before trusting the sticker on the controller. A "30amp" controller in reality can be anywhere between 15amps to 60amps.

Some folks sell controllers that shows a label that makes it duck the 750w law, but really it's a much higher current controller. Or more often, they de-rate a controller to be 20amps to let them use cheap parts and not blow, but sell it as a 30amp to be more appealing to customers. Or, it could be smack-dab on 30amps, never know. I would definately measure first before buying a breaker though.


Also, with DC, a breaker rated at perhaps 50amps at 12v will be lucky to last 1 trip cycle at at 48v or higher. It should trip fine, but it will take too long in breaking the arc, and likely will have high resistance when reset.

 

[Kevinator]

liveforphysics, great info! Thanks for the thorough explanation.

 

[fechter]

I use a pushbutton style circuit breaker on my Vego scooter. It's rated for 50A, but I routinely pull over 90A for short periods. I've held 60A for nearly a minute without tripping it. It's there to prevent a fire if the wiring or controller shorts. I've never had it trip. I also used a pair of 30A automotive type breakers in parallel on my Zappy. I did manage to trip those once, but they seemed to be pretty reliable at 24v. I'm not sure what they would do if they tripped with 72v though. It might turn into an arc welder inside.

 

[Lessss]

yes I use a circuit breaker
you can put multiple lower rated ones in parallel and the ratings add together.

 

[Kevinator]

Thanks for the additional info guys. I think I will stick with the ATC fuses or go with the Maxi's. Its a lot cheaper to replace those fuses than the push-button ones, if they're prone to increased resistance each time it pops.

 

[yopappamon]

A thermo-magnetic circuit breakers are slow acting, similar to a slow blow fuse. Just be aware of that before selecting.