# Can I use a fuse to control a motor's maximum output?

#### Richard England

Joined Jan 5, 2019
15
I want to limit the amount an electric hoist can lift by adding a fuse or circuit breaker to it. I did some testing and learned that a 2 Amp fuse will take a lot more current then 2 Amps, even a fast-acting one. I did some on-line research and discovered how little I really know about fuse and circuit breaker. I don't need to stop a lift if it's 10% over, 100% over is fine, but never more then that.

Question is can this be done, and how? By "how" I'm thinking that there might be a better method.

I know this sounds wild, and it may be, but I'm trying to create a point of failure that I can control.

#### Papabravo

Joined Feb 24, 2006
16,830
Why do you think this is a problem? In your view of how things work, what happens if the electric hoist is overloaded?

#### crutschow

Joined Mar 14, 2008
27,756
I would suggest a circuit breaker of the appropriate size.
It's a lot simpler to reset a breaker than to replace a fuse (where someone has to have a replacement handy.).

#### Richard England

Joined Jan 5, 2019
15
My concern is
Why do you think this is a problem? In your view of how things work, what happens if the electric hoist is overloaded?
This is not a simple hoist mounted above the object being lifted. It's mounted on the wall and via a series of pulleys running through the rafters, it can be located at a few different points. If it's lifting < 75 lb, and the motor is pulling 4 amps, something is wrong and something will break. I want it to be the fuse or something I can control.

Any idea I have is not unique, and since I could not find anyone that has done this, I'm doubting myself.

#### Richard England

Joined Jan 5, 2019
15
I would suggest a circuit breaker of the appropriate size.
It's a lot simpler to reset a breaker than to replace a fuse (where someone has to have a replacement handy.).
Agreed, but finding a circuit breaker of the appropriate size, with the correct calibration or time-current curve is harder than I expected.

#### nsaspook

Joined Aug 27, 2009
8,686
Agreed, but finding a circuit breaker of the appropriate size, with the correct calibration or time-current curve is harder than I expected.
That's because you really want power limiting instead of circuit/device protection.

#### LesJones

Joined Jan 8, 2017
3,498
Why not use a mechanical load sensor that triggers a micro switch. It could be as simple as a spring loaded mounting for one of the pulleys.

Les.

#### shortbus

Joined Sep 30, 2009
8,817
Not knowing what your calling an electric hoist makes things more complicated. Is is non reversible when the power is off, like a worm gear drive? Shutting down the power,like blowing a fuse, would allow the load to drop uncontrollably if the hoist was just a gear train with no holding power(think worm gear or similar). This is why most electric winches aren't rated for lifting, just pulling.

If you want to limit the amount of load that can be lifted you need a friction clutch of some sort. One that is adjustable to the accepted load to be lifted. this will keep it from even being lifted off the ground. Something like this, just the first item I found there are many more out there - https://www.ondrivesus.com/shaft-couplings-clutches/adjustable-and-fixed-torque-friction-clutches

Joined Jul 18, 2013
23,642
The rating for motor O/L and fusing is 1.5x the motor plate FLA rating.
Max.

#### Richard England

Joined Jan 5, 2019
15
That's because you really want power limiting instead of circuit/device protection.
Correct.

#### Richard England

Joined Jan 5, 2019
15
Why not use a mechanical load sensor that triggers a micro switch. It could be as simple as a spring loaded mounting for one of the pulleys.

Les.
That is a good idea....need to do some research to see if I can get or make one for a reasonable price.

#### Richard England

Joined Jan 5, 2019
15
Not knowing what your calling an electric hoist makes things more complicated. Is is non reversible when the power is off, like a worm gear drive? Shutting down the power,like blowing a fuse, would allow the load to drop uncontrollably if the hoist was just a gear train with no holding power(think worm gear or similar). This is why most electric winches aren't rated for lifting, just pulling.

If you want to limit the amount of load that can be lifted you need a friction clutch of some sort. One that is adjustable to the accepted load to be lifted. this will keep it from even being lifted off the ground. Something like this, just the first item I found there are many more out there - https://www.ondrivesus.com/shaft-couplings-clutches/adjustable-and-fixed-torque-friction-clutches
It's an HF hoist. I thought about a winch because I need a wireless remote for it, but I don't need that much power, I will be lifting so I want a break, and it needs to be 120AC.

I'm going to look into a friction clutch, it will require some modification to the mechanical part of the hoist, but since I have already added wireless to it, why not.

Joined Jan 15, 2015
6,065
You may want to give this a read. All of the cranes and hoist I have worked with in an industrial setting have one form of overload protection. Industrial US settings are required to have such protection. The link provides a few types and how they work.

Ron

#### Richard England

Joined Jan 5, 2019
15
You may want to give this a read. All of the cranes and hoist I have worked with in an industrial setting have one form of overload protection. Industrial US settings are required to have such protection. The link provides a few types and how they work.

Ron
Yes, that was a good read, it listed the 4 different methods of preventing an overload. So I have to pick one. I'm leaning towards using a weight sensor (<\$9 on Amazon) and somehow connecting it to a relay to interrupt power.

#### shortbus

Joined Sep 30, 2009
8,817
It's an HF hoist.
My middle son has one to use as an engine hoist. I guess If your using one of them and pulleys which I'm assuming you mean as a differential added lifting device why worry about load rating? If your only lifting 75 pounds you are barely making the hoist and cables work, no where near any of the limits of the equipment or original installed cable.

Joined Jan 15, 2015
6,065
Then you would use a load cell configured for tension. I would use it to interrupt up which will allow down. That's how they are normally configured. Anyway a load cell would work and if a certain weight limit is exceeded it will only allow down and not up.

Keep in mind this is OSHA and only applies to a business setting.

Ron

#### Richard England

Joined Jan 5, 2019
15
My middle son has one to use as an engine hoist. I guess If your using one of them and pulleys which I'm assuming you mean as a differential added lifting device why worry about load rating? If your only lifting 75 pounds you are barely making the hoist and cables work, no where near any of the limits of the equipment or original installed cable.
This hoist can only handle 220lb single line pull, plus I changed out the steel cable for a Kevlar rope. Still, I'm not concerned about the hoist or rope. My concern is the pulleys, rafters and a snag may drop the load. Most importantly, I have to go up there and fix it.

I decided to use an Arduino, load cell, LCD display, and relay to it. It would be cool to see the weight of each container. How hard can it be? Hahahaha

Thanks to everyone that chimed in!