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Electric Industrial Dolly Project


I am an engineering student and my capstone project is to design and build and electric cart to transport two welding cylinders. We have the cart designed and now we are trying to determine a motor size. Calling manufacturers hasn't gotten me anywhere.


~ 600 pounds

walking speed (~3 mph)

15 degree max incline

Can anyone provide guidance ?

Just a couple of safety concerns we had about the speed controller, does this prevent the motor from running while it is charging?  Does the charge port shut off when the motor is running?


The speed controller does not prevent the motor from running when a battery charger is plugged into the charger port. The charger port does not shut off when the motor is running or when the power switch is on.

The charger port wires are soldered directly to the battery wire posts inside of the controller, and they do not go through any electrical components that could control them.

If you have a requirement for the motor to not run when the batteries are charging, then it would be possible to bridge the positive terminal of the charger plug to the unused third charger plug terminal, and then have a relay energize from the third charger plug pin when it is plugged into the port. 

We carry 36 Volt power relays on this page: 
The order has been placed. Thank you for all your help. We appreciate you updating us!
How would we go about adding reverse to the system you sold us?
We carry a 36 Volt reverse relay that could be added to the dolly which would require a SPDT switch to operate it.

We also carry a rotary reverse switch that operates independently without a relay.


The benefits of the reverse relay and SPDT toggle switch are that the switch can be mounted away from the contactor so the heavy gauge controller to motor wires do not need to be ran to the location that the switch is in. The switch to relay wires can be a thinner gauge than the motor wires are such as 18 AWG or 20 AWG. The toggle switch is also easier to use and requires less force to switch between forward and reverse than the rotary reverse switch does. The reverse relay also has the benefit over the rotary switch of shorting the motor leads together when the toggle switch is in the off position which acts as a parking brake. The reverse relay has three modes: Forward-Park-Reverse

The benefits of the rotary reverse switch is that it costs less than the reverse relay and toggle switch. However the wires between the motor and controller need to run directly to the rotary switch which can limit the places where it is convenient to mount it. For example if the rotary switch was mounted three feet away from the motor and controller then there would be four quantity of three foot long thick gauge wires running between the motor/controller and rotary switch. The rotary switch is also larger and more difficult to mount than the toggle switch is. The rotary reverse switch has three modes: Forward-Neutral-Reverse.

The rotary reverse switch is our item # SWT-715 sold on this page:

The SPDT toggle switch that is used with the reverse relay is item # SWT-97 sold on this page:

We also have a handlebar mount SPDT rocker switch that can used with the reverse relay is item # SWT-39 sold on this page:

The reverse relay is item # RLY-RC36150 sold on this page:

Please let us know if you have any questions.

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