Looking for some help on a mechanical design

Main Question or Discussion Point

I'm a junior at my university in electrical engineering and we're tasked with created an original project for my electricity and magnetism theory class. I've come up with something I want to do, however a fair amount of the design for this project is pretty far out of what I know how to do. Anyway, I'm working through a particular part of how I could accomplish this project and was looking for some people who are more trained in this than I am to look over my idea (and perhaps correct me if I'm going the wrong direction).

One of the main parts of my project is that a weight will be raised, held, and lowered. I have the raising and holding design figured out for the most part, but for the lowering part, I am stumped as to how to go about the problem. I want the weight to be lowered at a low speed, as in, when I release the brake, I don't want the weight to drop as fast as gravity will take it.

I am looking for a cable reel which can spool (or raise the weight) unhindered, but when it unspools (lowers the weight), I want it to release at a slow rate (preferably constant rate). I'm a bit uneducated when it comes to the world of cable reels, so I was hoping someone around here may have an idea of what can be used. My original thought was getting a cable reel and then attaching a bike brake or something and have the release regulated like that. My only reservation is that the brake doesn't require any electrical power to operate

Any thoughts?

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Doug Huffman
Gold Member
There are a plethora of old fashioned mechanical regulators. For instance Watts/Farcot flying ball regulator/governor. The air motion regulator as in a music box.

I believe a winch is on the right track for what I need. The system will retract the cord when lifting a weight, a winch would do well due to the built in braking system. I just need a way to slow the extending speed (so that the weight doesn't drop too fast). The goal is to transmit the energy from the weight being dropped to spin a motor and generate electric current, hence why I don't want it to drop too fast. That's why I was thinking a brake like that found on a bike might do the trick nicely, but I'm pretty novice in this field and I'm not sure if its the correct way of going about this.

The electrical load on the generator will slow the weight. If you use a mechanical brake you will waste energy as heat you could have converted to electricity.