Using old motors as generators

stationary stu wrote:I know I should change but I still use a 240v lead lamp when working on the car etc and use rough service bulbs in that so looks as if I'll have to change soon. Problem is I don't like all these LED lamps that's about I just can't get away with the light they give off, it's probaby just me being old or something

Stu.

You may want to try the halogen based ones then, they are the same shape & size as the old bulbs, they just have a halogen capsule inside instead of a normal filament. I'll have to see if I can find any links.

I think for my JAP I would like to stick to a 12v system, I know the originals were 18v or 20v, but I could do with a decent 12v charging system at the rallies, as I tend to use up my caravan battery rather quickly. I'm not sure if there's a problem with the battery, the caravan electrics or possibly with the appliance I'm using, but I do seem to be able to knock the life out of my battery pretty quick with my little portable colour TV.
With a decent 12v charging set I could recharge the battery during the day, so I can fall asleep with the TV on in the evening for a couple of hours!

It shouldn't be too difficult to case it all in; The alternator could go inside a piece of large steel pipe, or even just make up a tin shroud, maybe even plastic pipe, painted to look like metal, some vent holes at either end, & small 12v batteries, either from an alarm system or RC model cars or even rechargeable lantern batteries (you can buy these sealed lead-acid lantern type batteries, 6v ones, for about £5 each these days) could be placed inside a metal box with a control panel on it, with an outgoing plug socket, or just terminal posts, a volt meter & ammeter, maybe a little charging light or something. It could easily be made to look the part, I reckon.

I found something that would make a cracking display but it's way to far from me and cash is a bit tight at present as always .
It's a 1940's temporary traffic light system it's all there lights, control box and a villiers engine (220v) it all needs fully restoring but at £120ono not a bad price for something different. It's collection only and in East Sussex if anyone interested pm me and I'll give you the details, it's in the Oct edition of Tractor and Machinery mag.

Nuts, I would be interested in them other bulbs if you can find the link please.

Stu.

nutgone wrote:I believe you will still be able to buy a type of energy saving bulb which will still be OK for stationary engine use, they are "dimmable Energy Saving Bulbs", they have a small halogen type capsule bulb inside what looks like a normal GLS type bulb (normal incandescent bulb). They are only class C on the energy efficiency scale, but they still count as energy saving.

Trouble is there are already dimmable CFL (compact fluorescent lamp) type bulbs, Last I heard there were 2 different types, one of which would work with normal dimmers, I'm not sure how "available" they are on the general market though.

It's people's desire to dim their lights which has kept the normal bulb going so long, & although these halogen ones are better they're still not very efficient compared to CFL's.

I say these are suitable for stationary engine use as many engine generators are producing DC, which won't power CFL's, but it will power the halogen type ones, also many stationary engine generators aren't running at full voltage, which will also make CFL's fail to light.
Also, who wants a load of ugly CFL's in front of their lovely engine set-up?

Fortunately mine is a 110v generator, AFAIK there are no plans to make building sites start using low energy lighting, so I will still be able to get my good old fashioned incandescent bulbs. Also, the 110v bulbs are "Rough Service" not "general Service" which means they are made of stronger stuff, both inside & out. Still don't like being stepped on though!

So, if it's 230v bulbs you're after you should be fine if you look around for halogen based "Dimmable Low Energy" bulbs,
If it's 110v bulbs you're after, go to any electrical wholesaler & ask for 110v site bulbs, they're all 60w & mostly pearl, although I thing clear are available.
This should keep your exhibit looking something like it should.

http://www.toolstation.com/shop/Lighting/Energy+Saving+Halogen+Retrofit/Sylvania+Halogen+GLS+Energy+Saver+42w+BC+600lm/d220/sd3277/p83772

Thank you Blackvanman, that's exactly the ones I was on about.

Thanks guys for the info, I use Tool Station next time I'm passing I'll call in and get a few.

Stu.

nutgone wrote: even rechargeable lantern batteries (you can buy these sealed lead-acid lantern type batteries, 6v ones, for about £5 each these days)

Where are these from Matt and any idea of capacity? I need a battery for one of my motorbikes but there's no way I'm parting with 35 quid for a 6 volt lead acid battery...... Plus if I get a sealed one I can hide it better.

nutgone wrote:Thank you Blackvanman, that's exactly the ones I was on about.

I got some of these in the 70w flavour to use in my blast cab. I got them from tesco for 75p each.

pauldg wrote:

nutgone wrote:Thank you Blackvanman, that's exactly the ones I was on about.

I got some of these in the 70w flavour to use in my blast cab. I got them from tesco for 75p each.

That's a good price I'll look next time I'm in Tescos.

Stu.

OK, back on track, I've been doing some work on the reason I started this thread (did I start this thread? ..... Oh yes, so I did).

I've been taking this old motor apart, but before I get on to that I've been researching how to make 3 phase motors into generators with the use of some capacitors, it all looks relatively simple (I saw it on another "not so friendly" forum, I think). I thought it would be of no use, as this is a single phase motor, but I seem to remember from my days at college, learning to be an electrician, that you can run 3 phase motors from a single phase supply, & as I started to dismantle this motor it would seem it may be a 3 phase unit after all, but I would like someone "in the know" to give me their opinion on it as well, before I just go ahead & connect it up.

Basically the motor is a very large one, quite old, with 2 huge capacitors on top. The plate reads like this (I took 2 pics of it, just to get it all in focus)....




I looked at the wiring & both capacitors were wired together. There were 4 terminal posts in there, plus an earth. After removing the end plate I found a centrifugal switch inside....





This switch seems to connect the capacitors to the AC supply, via one (or two) of the coils. I seem to remember reading about these during my training, I think it's a pretty old way of getting a 3 phase motor to work on a single phase supply, using the capacitors to knock the phase out in order to create a kind of "2 phase" system to get the motor started (rotating magnetic field) & disconnecting this when the motor is up to speed.
Am I right???

Here's a very rough sketch of how it's wired up. I tested the 6 wires going into the stator coils to find out which ones were connected. Basically there are 2 blue wires (labelled Bl1 & Bl2), 2 red wires (labelled R1 & R2) & 2 black wires (also labelled Bl1 & Bl2 for some strange reason I guess I knew where they were). Anyway, for now, the black wires went to terminals 3 & 4 on their own, the blue & red ones went one of each onto posts 1 & 4. I will re-do this sketch later, to make it a bit more understandable (can't believe I labelled blue wires Bl & black wires the same!!! !!!) anyway, here goes...



Here's a general pic of the inside of the motor, showing the "squirrel cage" rotor....




What I basically want to know is; Is this a 3 phase motor? & Can I just wore it up by joining the ends of each coil, connecting a capacitor to each one & taking my phases off there? (Or using the "C + 2C" method to get single phase from it). Any idea what voltages I will get??? I'm guessing a P/F correction cap off a florescent light will do the trick??? (I'll have to re-check the thread for the values).

It says single phase / 240 volts on the plate and correct me if I'm wrong I thought 3 phase worked on 440 volts and single phase on 240 volts, so to me I'd say it was just single phase.

Stu.

It's a bit complicated to explain, but you can run 3 phase motors from single phase supplies, with the aid of capacitors. I'm not sure it's common practise these days, but it did used to be.

I'm pretty sure the centrifugal switch on this one has something to do with it. I seem to remember that the motor isn't anywhere near as powerful, but it can be done.

I'm sure someone will come along soon & correct me if I'm wrong. I suppose I should look into it myself, but I'm currently researching something else, which is taking up most of my time.

nutgone wrote:It's a bit complicated to explain, but you can run 3 phase motors from single phase supplies, with the aid of capacitors. I'm not sure it's common practise these days, but it did used to be.

I'm pretty sure the centrifugal switch on this one has something to do with it. I seem to remember that the motor isn't anywhere near as powerful, but it can be done.

I'm sure someone will come along soon & correct me if I'm wrong. I suppose I should look into it myself, but I'm currently researching something else, which is taking up most of my time.

correct

it is a single phase motor, it needs the capacitor as a running cap, the only reason you have 2 caps in parallel is probably because someone had 2 caps of half the value req for running, caps work opposite of resistors when using two or more together, in series the capacitance is reduced in parallel it is increased. so really you only need one cap of correct value to make the motor run, on the plate it looks like it says condenser 140MFD so I think it wants 140uf the 2 caps you have there should add up to that figure.

As far as running as gen set goes, never done it, hence no previous comment

You're right about the caps, one is an 80uf the other is a 60uF (it did say on them, but had been painted over, so I measured them on my L/C meter, they are typical motor caps really, very leaky.

The centrifugal switch has got me thinking though, these caps are wired through this switch, so when the motor is up to speed the caps & one or two of the coils are disconnected, kinda reminded me of a star/delta starter, which is really old-school these days.

There are definitely 3 separate coils in the stator though, which makes me think it will work as a 3 phase genny, or single phase with the C-2C connection method. Just dunno what the voltage will end up being.

Might have to take this one somewhere else, but will keep this thread updated if I find anything out.

stationary stu wrote:It says single phase / 240 volts on the plate and correct me if I'm wrong I thought 3 phase worked on 440 volts and single phase on 240 volts, so to me I'd say it was just single phase.

Stu.

just to confuse you Stu, you can have 240v 3ph as well lol

blackvanman wrote:

stationary stu wrote:It says single phase / 240 volts on the plate and correct me if I'm wrong I thought 3 phase worked on 440 volts and single phase on 240 volts, so to me I'd say it was just single phase.

Stu.

just to confuse you Stu, you can have 240v 3ph as well lol

I'm working on a boat with that at the moment, very off-putting when I couldn't find any neutrals!

nutgone wrote:

blackvanman wrote:

stationary stu wrote:It says single phase / 240 volts on the plate and correct me if I'm wrong I thought 3 phase worked on 440 volts and single phase on 240 volts, so to me I'd say it was just single phase.

Stu.

just to confuse you Stu, you can have 240v 3ph as well lol

I'm working on a boat with that at the moment, very off-putting when I couldn't find any neutrals!

he he he

[quote="blackvanman
just to confuse you Stu, you can have 240v 3ph as well lol[/quote]

I'm already confussed not difficult I know, I never knew electrics were so complicated, I just thought to get an electrician you just kick the brains out of a mechanic

Ok if your still speaking to me you have to explain 240v 3ph but not now as I don't want to take over the thread.

Stu.

stationary stu wrote:
I just thought to get an electrician you just kick the brains out of a mechanic
Stu.

No, that's a plumber!

Ok I've picked up a 12v dynamo on ebay for 99p so I'm going to be having a play with that, just need to find a cheap regulator box box now.
Are dynomo's directional and if so how do I find out? if my questions get out of hand I'll start my own thread

Stu.

stationary stu wrote:

Ok I've picked up a 12v dynamo on ebay for 99p so I'm going to be having a play with that, just need to find a cheap regulator box box now.
Are dynomo's directional and if so how do I find out? if my questions get out of hand I'll start my own thread

Stu.

Not sure about direction, but I know they are either positive or negative earthed & you can change that with the aid of a battery.

I'm guessing as they are a DC generator they will be directional, but really I'm not sure on that.

Thanks for the info Nuts once I get it I'll check it out and see what's what.

Stu.

I've been told they can run in either direction, but please don't quote me on it (it's 2nd hand information).

As for regulators, if you get the speeds matched up & the governor is working correctly on your engine you don't need a regulator with a dynamo. Well, the Tarpen is a dynamo & that doesn't have a regulator on it, it is entirely regulated by engine speed.

Someone's bound to come along now & tell me that's wrong, it may well depend on how the dynamo is wound (IE: shunt or compound wound) but as far as I know you should be able to regulate it by engine speed (the cheap way) but you may need to wire two terminals together in order to do it.

Changing polarity is easy, but will only be necessary in certain circumstances, light bulbs don't mind which way you wire them up.

I wish I could find a dynamo for 99p!

I understand that dynamo's can rotate either way but if it is a used one it is advisable to turn the brushes round so that they dont catch the commutator when it runs in reverse?

Pete.

Foden wrote:I understand that dynamo's can rotate either way but if it is a used one it is advisable to turn the brushes round so that they dont catch the commutator when it runs in reverse?

Pete.

Good point, I was just gona say that, honest,

If you are unsure which direction it was rotating in you can always re-cut the brushes in with some wet & dry paper, or emery cloth on the commutator, they may be ok anyway & should soon wear correctly, but Pete's right, there is a danger you can chip a brush (or worse) if you reverse rotation.