Looking for some help....Motor woes
- Thread starter GraemeD
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GraemeD
Established Member
Thanks Roy, that's easy to fix if that's the case.
So, how tight should it be? It's an ordinary vee belt, and I just made it good and taught.....though I noticed it was quite hard to pull off the lower wheel when I wanted to check the friction by hand!
My thought on the bigger cap was simply that it's less additional hardware to add. It kind of achieves the same goal with more juice in the same time period, rather than the normal amount of juice but for longer. I dunno!
Graeme
So, how tight should it be? It's an ordinary vee belt, and I just made it good and taught.....though I noticed it was quite hard to pull off the lower wheel when I wanted to check the friction by hand!
My thought on the bigger cap was simply that it's less additional hardware to add. It kind of achieves the same goal with more juice in the same time period, rather than the normal amount of juice but for longer. I dunno!
Graeme
As I don't know the distance between the pulleys I can't give you a figure, but just tight enough so that it does not slip.
Trial and error!
That, if the cause of the heating, might well solve you start problem as well by reducing friction.
Increasing the capacitor size will probably work, but could shorten the winding life, so could extending the start up time, but a variable timer would allow you to set the minimum time, thus minimising any possible threat to the windings IMO.
Roy.
Trial and error!
That, if the cause of the heating, might well solve you start problem as well by reducing friction.
Increasing the capacitor size will probably work, but could shorten the winding life, so could extending the start up time, but a variable timer would allow you to set the minimum time, thus minimising any possible threat to the windings IMO.
Roy.
GraemeD
Established Member
Thanks for the info Roy. The distance between the pulleys is something like 2ft, if that helps!
During my initial experiments I did slacken off the belt by a large amount, in case this extra compliance it offered allowed the motor to get going. It didn't have any effect, and although there was no slippage, the belt did seem to resonate a bit at times, hence I put back the tension.....probably more than I intended to be honest. I'll back it off as you suggest and see if it runs cool, like the bearing at the other end.
You're right about the timed start.....it seems more controllable, and is therefore probably a better long term solution. I'll start looking into this once I get some spare time (back at work for the week now...).
Graeme
During my initial experiments I did slacken off the belt by a large amount, in case this extra compliance it offered allowed the motor to get going. It didn't have any effect, and although there was no slippage, the belt did seem to resonate a bit at times, hence I put back the tension.....probably more than I intended to be honest. I'll back it off as you suggest and see if it runs cool, like the bearing at the other end.
You're right about the timed start.....it seems more controllable, and is therefore probably a better long term solution. I'll start looking into this once I get some spare time (back at work for the week now...).
Graeme
Vibrating belts usually means too slack, but two feet on a slim belt it is likely anyway. Normal running shouldn't produce any noticable warmth on the bearing.
A simple CR timer with part of the R as a Pot should give a controllable time, from your posts it seems that you only need a relatively small increase.
This brings on memory lane time.
I walked into my mate's workshop years ago and my mate stopped the mill he was using. He had the same problem as you are facing.
On this mill the motor was at floor level, so **** had a piece of wood on small piece as a rocker with one end under the motor.
To start up he put his foot on the length of wood, this lifted the motor and slackened the belt.
With the motor upto speed he took his foot off of the wood.
"Crickey ****!" I commented, "that's a bit crude!"
His reply?
"This is the Mark Two, you should have seen the Mark One!"
Roy.
A simple CR timer with part of the R as a Pot should give a controllable time, from your posts it seems that you only need a relatively small increase.
This brings on memory lane time.
I walked into my mate's workshop years ago and my mate stopped the mill he was using. He had the same problem as you are facing.
On this mill the motor was at floor level, so **** had a piece of wood on small piece as a rocker with one end under the motor.
To start up he put his foot on the length of wood, this lifted the motor and slackened the belt.
With the motor upto speed he took his foot off of the wood.
"Crickey ****!" I commented, "that's a bit crude!"
His reply?
"This is the Mark Two, you should have seen the Mark One!"
Roy.
GraemeD
Established Member
Nice story! javascript:emoticon('
') Certainly made me smile.....
Do you have any suggestions for the RC delay circuit? I'm now struggling in my mind with doing things with mains voltages! I have some relays with 240VAC coils....I also have some lower voltage DC ones. I'm guessing using an AC one would be easiest, as it won't needs a power supply of any kind. But how to drive it? Am I being stupid as to how to take this forwards? Being a chip designer, the combination of mains and electronics makes me nervous!!
Graeme
') Certainly made me smile.....Do you have any suggestions for the RC delay circuit? I'm now struggling in my mind with doing things with mains voltages! I have some relays with 240VAC coils....I also have some lower voltage DC ones. I'm guessing using an AC one would be easiest, as it won't needs a power supply of any kind. But how to drive it? Am I being stupid as to how to take this forwards? Being a chip designer, the combination of mains and electronics makes me nervous!!
Graeme
http://www.northcountryradio.com/PDFs/column008.pdf
There's the basic circuit, couldn't be much simpler.
Roy.
There's the basic circuit, couldn't be much simpler.
Roy.
9fingers
Established Member
I'd raid an defunct but relatively modern toaster. Many now use a cmos 4060 binary divider and a simple rc oscillator to hold in a relay for the toasting time.
The big advantage is that the circuit is usually designed to run from 240 ac and will include an economy power supply.
Reduce the timing capacitor by say a factor of 10 or more and you should get the sort of time range you need.
Experiment using an isolating transformer as the whole circuit will be live and then when you are happy with it, pack it in a plastic box and use the output to drive one of your mains relays.
Bob
The big advantage is that the circuit is usually designed to run from 240 ac and will include an economy power supply.
Reduce the timing capacitor by say a factor of 10 or more and you should get the sort of time range you need.
Experiment using an isolating transformer as the whole circuit will be live and then when you are happy with it, pack it in a plastic box and use the output to drive one of your mains relays.
Bob
DaveL
Established Member
I may of told this story before but I think it well rate with the MK1 version of Dicks. As a teenager I worked in a small builders yard, making fence panels. My build bench was at the back of the shed where the table saw and planer lived.Digit":12byd3dy said:
The planer had a 2hp single phase motor that in the cold weather would blow the fuse in the main building, taking the whole shed supply. Even with the belt off on frosty mornings this would happen. We used to take the belt off, wrap 3 or 4 foot of string on the motor pulley, pull hard and then hit the power. Once the motor had run for a few minutes the belt was flicked on with a stick.
Don't try this at home, or work for that mater and yes I do still have all of my fingers.
This really has turned into an applicable topic for someone called Digit and someone called 9Fingers!!
Keep it up guys - it's good entertainment.
Bob,
I do like your idea of the toaster timer. Next time I'm at the skip I'll see if there's any lying about. I was about to say to Graeme that he should go down the adjustable delay timer from Farnell, etc., rather than experiment with 555's and the likes as the kit he's experimenting on and the power floating about make experimental circuits a hazard, but the toaster timer will probably avoid to many risks.
We discussed earlier adding a comment to your induction motor pages on this problem; may I make the suggestion that you do add something as this is clearly a real problem, and an on-going one to boot. The follow-on problem is the potential overheating of the starter winding - now my electronics is sufficiently well developed that extending the time would have been easy, but my motor knowledge would have lacked the point about the reduced copper in the starter winding and I wouldn't have been aware of this risk. Graeme has been made aware of this risk, and for my workshop I would share his philosophy of accepting it, but if was doing this for an industrial or club situation I do now at least know about it and I wouldn't accept that risk.
I'm sure that you can word such information in such a way that your integrity is not challenged
Rob
Keep it up guys - it's good entertainment.
Bob,
I do like your idea of the toaster timer. Next time I'm at the skip I'll see if there's any lying about. I was about to say to Graeme that he should go down the adjustable delay timer from Farnell, etc., rather than experiment with 555's and the likes as the kit he's experimenting on and the power floating about make experimental circuits a hazard, but the toaster timer will probably avoid to many risks.
We discussed earlier adding a comment to your induction motor pages on this problem; may I make the suggestion that you do add something as this is clearly a real problem, and an on-going one to boot. The follow-on problem is the potential overheating of the starter winding - now my electronics is sufficiently well developed that extending the time would have been easy, but my motor knowledge would have lacked the point about the reduced copper in the starter winding and I wouldn't have been aware of this risk. Graeme has been made aware of this risk, and for my workshop I would share his philosophy of accepting it, but if was doing this for an industrial or club situation I do now at least know about it and I wouldn't accept that risk.
I'm sure that you can word such information in such a way that your integrity is not challenged
Rob
GraemeD
Established Member
I'm more than happy to go down the 555 timer route (blimey, that takes me back....I'd just have to use Veroboard too, to make it authentic!), but the faff of having to rig up a PSU alongside does put me off a bit. Maybe I'm being overly negative here, as it's a good solid way to achieve the result. The Farnell type timer relay is the easy way out, and if I could pick one up at a good price, I'd be happy with this. Ebay didn't come up with any bargains that I could find....
However, the toaster idea is truly inspired! I love this, and would be more than happy playing with 4000 series CMOS again....that was what I learned with back in the late 70s! So, would any toaster labelled "electronic" have something like this inside? I'm sure I can come up with something from Freecycle if I scout around!
Graeme
However, the toaster idea is truly inspired! I love this, and would be more than happy playing with 4000 series CMOS again....that was what I learned with back in the late 70s! So, would any toaster labelled "electronic" have something like this inside? I'm sure I can come up with something from Freecycle if I scout around!
Graeme
9fingers
Established Member
Graeme,
I would think that any toaster marked electronic will be a suitable donor.
The quick test I would apply is to press the button down to start the toasting process with the power OFF. If the button latches down mechanically then this might not be a suitable one and is likely to have the older bi-metal sensor in. These attempted to sense the amount of heat reflected off the cooking toast to see when it might be done.
Electronic ones use a solenoid latch and so will not latch with the power off.
The 4060 chip is a very useful timer. It comprises an RC oscillator support circuit driving a very long divider chain with most of the outputs available. To make a long timer, the chosen divider output is fed back to the oscillator enable. These devices enable delays of hours to be obtained with modest R C values and of course CMOS impedances allow large values for R- say up to 10Mohms before the timing calculation is affected by gate leakage.
Happy foraging!
Bob
I would think that any toaster marked electronic will be a suitable donor.
The quick test I would apply is to press the button down to start the toasting process with the power OFF. If the button latches down mechanically then this might not be a suitable one and is likely to have the older bi-metal sensor in. These attempted to sense the amount of heat reflected off the cooking toast to see when it might be done.
Electronic ones use a solenoid latch and so will not latch with the power off.
The 4060 chip is a very useful timer. It comprises an RC oscillator support circuit driving a very long divider chain with most of the outputs available. To make a long timer, the chosen divider output is fed back to the oscillator enable. These devices enable delays of hours to be obtained with modest R C values and of course CMOS impedances allow large values for R- say up to 10Mohms before the timing calculation is affected by gate leakage.
Happy foraging!
Bob
9fingers
Established Member
OldWood":1m920mef said:This really has turned into an applicable topic for someone called Digit and someone called 9Fingers!!
Keep it up guys - it's good entertainment.
Bob,
I do like your idea of the toaster timer. Next time I'm at the skip I'll see if there's any lying about. I was about to say to Graeme that he should go down the adjustable delay timer from Farnell, etc., rather than experiment with 555's and the likes as the kit he's experimenting on and the power floating about make experimental circuits a hazard, but the toaster timer will probably avoid to many risks.
We discussed earlier adding a comment to your induction motor pages on this problem; may I make the suggestion that you do add something as this is clearly a real problem, and an on-going one to boot. The follow-on problem is the potential overheating of the starter winding - now my electronics is sufficiently well developed that extending the time would have been easy, but my motor knowledge would have lacked the point about the reduced copper in the starter winding and I wouldn't have been aware of this risk. Graeme has been made aware of this risk, and for my workshop I would share his philosophy of accepting it, but if was doing this for an industrial or club situation I do now at least know about it and I wouldn't accept that risk.
I'm sure that you can word such information in such a way that your integrity is not challenged
Rob
Rob, Maybe Roy (Digit) and I would make a good team! :lol:
It certainly seems that he and I have a number of common interests other than woodwork.
Equipped with the newly acquired knowledge from this thread and the recent research I have been doing as a result, I will indeed be revising my motor document to include something about this potential problem.
Bob
9fingers
Established Member
I was self taught with valves as a lad building the electronics for my reel to reel tape recorder from EF86, ECC83 and EL84s plus EZ81 in the power supply.
I've never designed motors - just used them all my life - again self taught.
I reckon between us we could fix most things though!
Bob
I've never designed motors - just used them all my life - again self taught.
I reckon between us we could fix most things though!
Bob
ECC82 - ahh.. that takes me back to schooldays (~1959) when I used one for a school science fair to make a ping pong ball in the middle of a sheet of ply disappear when you reached for it due to body capacitance.
Memory says I never used a valve again, but then I did have a neighbour who worked an electronics plant.
Rob
Memory says I never used a valve again, but then I did have a neighbour who worked an electronics plant.
Rob
I was Mister in between. I got involved in electronics via model aircraft, so by the time I got to college I was ok on valve usage. At the time it was obvious that the future was semi conductors, but anything that came in for repair was gonna be valve based for some years, so we were taught semi-conductor theory as a side line.
The first transistor radio I repaired was a Roberts, wooden cased like the current 'retro' model.
Each set was supplied with a small bottle of adhesive to glue the copper lands back onto the paxolin, 'cos if the set got hot the copper expanded and lifted off!
Leave 'em in the sun and thermal ranaway was likely!
LSI was years in the future!
My first home brew was OC71s and 2s and OC35s, now you know how old I am! :lol:
Roy.
The first transistor radio I repaired was a Roberts, wooden cased like the current 'retro' model.
Each set was supplied with a small bottle of adhesive to glue the copper lands back onto the paxolin, 'cos if the set got hot the copper expanded and lifted off!
Leave 'em in the sun and thermal ranaway was likely!
LSI was years in the future!
My first home brew was OC71s and 2s and OC35s, now you know how old I am! :lol:
Roy.
When I proposed to my wife Rob I told that whatever the future might hold it would never be dull!
I was 29 and new what my life was like, it began in a burst of machine gun fire that wrecked the front of our house, causing my mother to go into labour and I was born on the floor amongst the wreckage.
September 1940!
Even the date is in doubt. Mum said it was the 12th and dad said it was the 20th!
At the age of 4 Hitler had another go at me and I was buried by bomb blast!
So like I said, never a dull moment! :lol:
Roy.
I was 29 and new what my life was like, it began in a burst of machine gun fire that wrecked the front of our house, causing my mother to go into labour and I was born on the floor amongst the wreckage.
September 1940!
Even the date is in doubt. Mum said it was the 12th and dad said it was the 20th!
At the age of 4 Hitler had another go at me and I was buried by bomb blast!
So like I said, never a dull moment! :lol:
Roy.
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