DIY Electric Car Forums banner

1 - 3 of 3 Posts

·
Registered
Joined
·
4,302 Posts
Discussion Starter #1
In several threads I've heard people remark that current reversing requires expensive contactors. Why is that? If you turn off the current and simply used a two-position two-pole heavy knife switch wired for forward in one position and reverse in the other, it seems to me that it would work just as well? I've seen golf carts with a similar setup - a rotary knob with F/N/R.
 

·
Registered
Joined
·
7,829 Posts
In several threads I've heard people remark that current reversing requires expensive contactors. Why is that? If you turn off the current and simply used a two-position two-pole heavy knife switch wired for forward in one position and reverse in the other, it seems to me that it would work just as well? I've seen golf carts with a similar setup - a rotary knob with F/N/R.
Hi Phant,

Yeah that works for golf carts at the relatively low voltage and currents associated with that application. And the motor, controller and battery are under the seat where the switch is located.

When you get into higher voltage and current, the switch itself becomes a problem with contact burning due to low separation speeds and such. The switch to do the job becomes as expensive as contactors. And then you have the heavy cables required to connect the switch to the circuit and locate it in hands reach. It also puts the high voltage wiring within hands reach on the dashboard or elsewhere in the cabin.

Not a good idea for EV cars :(

Regards,

major
 
1 - 3 of 3 Posts
Top