Adjustments that need to be made to a Speed Regulator

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
I have a project I have been working on, that has me out of my depth with regard to my knowledge, as I am a very basic electronic hobbies.

It comprises of a 24V D.C electric motor, 200W, 3,000 rpm, 13A. which has a pulley, a belt from this attaches to a pulley on a drive shaft, where a flywheel is situated, and on the other end, is a pulley, with another belt, that goes to a 230v AC alternator.
The motor is controlled by a Electromen EM-285 DC-Motor speed regulator 12 / 24V 20A. The regulator has three adjustable potentiometer, a Range trim, Current limit, and load compensation.
On the leaflet that came with the regulator for the installation, there is information that someone who works with electric motors, and speed controllers, which have potentiometer. Will know how to go about adjusting them to get the optima setting’s. But which has left me slightly baffled with my basic knowledge of electric motors, and electronics.
So I contacted the manufactures to see if they could help me, unfortunately they just repeated what was on the leaflet. But they did go off script a little, to quote from there email “There is no specific guidelines on setting the current-limit, I suggest experimenting until you find something that suits the application in question, start low and then increase”

So I experimented and found that if I sent the Range trim at a certain setting, and the current at another, the load compensation I left at zero.
With just the belt attached from the electric motor to the drive shaft, when I turned on the speed regulator, and increased the speed setting, the shaft started turning, I further increased the speed, and it picked up, and was moving very fast.
I then turn the speed down, and it slowly lost speed, until it was just turning over, and then I slowly turn the speed up to a 100% again, and the flywheel whizzed around.

Next I attached the belt from the pulley on the drive shaft to the one on the alternator. Turned on the speed regulator, and slowly increased the speed, but this is when I found I had a problem, it would only rotate slowly. I put the speed controller up to 100% but it made know different to the speed.

The alternator shaft runs on two bearing, you can spin the pulley on it, with your hand, and it will do a couple of revolution before it stops, so there is know great resistants from the alternator spinning.
Also there is not a great difference in the force one has to use to spinning the flywheel by hand with just the electric motor being connected to the drive shaft. To when I then attach the belt from the pulley, to the alternator, and then spun it by hand.

But logic dictates, that I lost the speed, that I had before, (which I must point out was really fast). When I attached the other belt that goes to the Alternator.
So is the answer to the lost of speed, down to the adjustments of the Potentiometer, to be quite frank, Range trim, Current Limit, and especially Load compensation, I have a lack of knowledge and experience of working with.
I did go online to see if I could improve my knowledge, which I did to some extent.

So I did a little experiment, and increased the Current limit which certainly made a difference to the speed. As the test was progressing there was a smell of melting plastic. Looking at this fuse, that, protects the electric motor which is a spade type, that are used in motor car, the plastic casing was melting!, it was acutely bubbling! but the fuse had not blown, so I turn off the power. Let everything cool down, put a new fuse in, and did a quick test, and everything worked o.k, so nothing else was damaged.

Any thoughts, and suggestion on what the problem is, and how to go about fixing it, would be much appreciated.
 

Alec_t

Joined Sep 17, 2013
14,313
1) What is the current/power rating of your power supply? It may be insufficient.
2) If your motor is rated for 13A current at 3000rpm it will draw (or try to draw) several times that current (perhaps >50A) at low speed during start up. The start-up phase will be lengthy in view of the inertial load presented by the flywheel and alternator. Your power supply may therefore be going into self-protect mode and reducing (or shutting off) its output voltage.
 

Irving

Joined Jan 30, 2016
3,885
So this is a DC to AC generator set with around 100-150W output at 230v. Some pictures would be helpful, but this is an old and very inefficient way to generate AC from DC.

The speed the motor runs at is important, as that will determine the frequency of the AC which should be 50 or 60Hz depending on where in the world you are.

What size was the fuse and what are you powering the motor from - a power supply or batteries?

The basic arrangement would be to set the range to max, compensation to min and current limit to max initially. The current limit will determine the ability of the motor to start under load and to drive the shaft. Too low and nothing happens, too high and the wiring to the motor may be compromised if its not sufficient for the required current when the motor is under load, or worse, if it stalls.

You need to set the current limit to a level which allows the motor to start easily when nothing is plugged into the alternator. Then adjust the motor speed to give the required output frequency. the motor is rated for 3000rpm at 24v so this is the nominal speed. The alternator should be marked with a speed rating too. 3000rpm for a 50 or 60Hz output wouldn't be unusual., in which case the pulley ratios would be 1:1 but your pulleys may differ. Once that is set then load compensation is increased a little at a time so that the motor speed doesn't change when a load is attached. You may need to tweak the current limit higher if max compensation doesn't stop the motor speed dropping when a load is attached.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
Thank you for your reply to my thread, the power supply is a 300w AC-DC converter AC 220v-230v to 24v 12.5-15A power switching transformer. Which I note has over-load, over-current & short-circuit & temperature protection.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
Irving. Thank you for your reply, with your evaluation of the problem, I will in the next couple of days post the information, and hopefully a picture that you asked for.
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
The ideal behind my project came about because of the hike in energy / fuel prices, we all felt here in the UK.
I had seen a video clip’s on U tube about flywheel’s, and wondered if it would be possible to use the force of a flywheel momentum, driven along by a low voltage, low wattage, electric motor, and connected to an alternator, to produce my own electricity. Of course the motor might struggle to turn the flywheel to start with, (which weighs 22.5 kg), but if I spun the flywheel first, and then turn the motor on, it would not be trying to turn a dead weight.

I based my thinking on this ideal, that I had, around when riding a bike, when you are going down a gentle slop, if you carry on peddling, its really easy, no great force of energy is required from you, so you burn less energy. So once the flywheel has some momentum behind it, the electric motor is under know great resistants when rotating.

The alternator I purchased is made in Italy, can be run by a petrol or diesel engine, (an expensive way to produce power now, because of the fuel prices) or you can buy a pulley kit, as I did.
The Alternator is single phase, brushless unit, 115/230 volts, 50 Hz 3000rpm, the output on this model is 8.5 kva.
The sales person in the UK that I dealt with, who company import, and sell them, informed me that you need to get the alternator turning at 3100 rpm, to allow for the drop in speed of the alternator, when you start to draw power. I will mention here that the type of electricity that this type of alternator produces, will only power electric items that do not have any circuit boards within them. So any basic type of heating unit's will work, on this power supply, which is what I was looking to power.

I have attached some photographs of the test rig that I set up. I will mention here also, that one rotation of the large pulley, turns the smaller pulley on the alternator four and three quarter rotation, so this has allowed me to greatly reduce the rpm that the electric motor needs to spin at.

I had of hoped to post this thread earlier, but decided to to carry out another test run, this time with the flywheel removed. again the same problem the maximum rpm I could reach was 290. So disconnected the belt from the pulleys and ran the motor again, well the large pulley was really flying round, a lot faster than when the belt was attached, another thing I noticed at the same time, was that I had a better control of the speed, when I increase and decreased the speed. than when I had the belt connected to the alternator, when there was a load.

So it might be, which has been mention in a couple by of replies to my thread, that the power supply, which comes from a 300W AC-DC converter (which I have given the details about), might not be powerful enough to cope with turning the alternator, I have attached a photo of the power supply as well.

Any other thoughts and suggestion with the extra information I have given, would be much appreciated.
 

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crutschow

Joined Mar 14, 2008
34,427
wondered if it would be possible to use the force of a flywheel momentum, driven along by a low voltage, low wattage, electric motor, and connected to an alternator, to produce my own electricity
Sorry, but you can never get more energy out of the the system then you put in (commonly called over-unity or perpetual motion)
You are wasting your time.
 

Irving

Joined Jan 30, 2016
3,885
Any other thoughts and suggestion with the extra information I have given, would be much appreciated.
Sadly, I have to agree with @crutschow - this cannot work. Even if you could get the alternator up to speed with no load, as soon as you connected the load it would stop. When you are coasting downhill on a bike you are converting your potential energy at the top of the hill to kinetic energy as you go down. The potential energy came from the effort you put in to climb the hill in the first place - it wasn't magically created when you started going downhill. Energy can neither be created nor destroyed - it can only be converted from one form to another, usually not perfectly as there are always losses through heat, etc. due to friction. In the words of the great engineer Scotty, "Ye cannae change the laws of physic, Cap'n"
 

Thread Starter

Drew . G. H. 1066

Joined Feb 14, 2023
27
Sadly, I have to agree with @crutschow - this cannot work. Even if you could get the alternator up to speed with no load, as soon as you connected the load it would stop. When you are coasting downhill on a bike you are converting your potential energy at the top of the hill to kinetic energy as you go down. The potential energy came from the effort you put in to climb the hill in the first place - it wasn't magically created when you started going downhill. Energy can neither be created nor destroyed - it can only be converted from one form to another, usually not perfectly as there are always losses through heat, etc. due to friction. In the words of the great engineer Scotty, "Ye cannae change the laws of physic, Cap'n"
Thank you for taking the time to reply to my posting, with it conclusion, that I was on a mission impossible with this project.
 
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