electric motor/ single speed/ 600 -800 revs

[zongatron]

Hi again guys.

Thank you very much for your replies, they have been very helpful.

I have spent a couple of days field testing my spin art box ( I used a pottery wheel which is too slow but still had the general idea with a variable speed pedal) and for the moment variable speed motors are now not needed.

https://www.youtube.com/watch?v=8h1Ci0nAnI4

I initially thought it would be a good idea for the kids to be able to control the speed so they can choose how the art comes out. BUT they just end up playing with the speed controller instead of doing any art! :) (SHould have known)

I will investigate variable speed in the future when building machines for myself and adults etc.

So now I just need a single speed motor that runs at about 6-800 rpm.

Single on off switch.

Needs to work for five or six hours a day on and off.

Only needs to take the weight of a 30cm x 40 cm light wooden framed canvas and a metal jig to hold it.

Needs to be safe as kids will be using it at schools etc.

I'm thinking a washing machine motor would be overkill, and use unnecessary power. Bit of overkill.

Thanks again

Ben

[Robson Valley]

First step is to get the prototype built out of whatever junk parts you can grab.
Would it be safe enough for a faster speed motor and a pulley/belt drive to reduce the table rpm?

Plan B: strap a cane toad to the table, turn it on and go away for the weekend.

[BobL]

I'm thinking a washing machine motor would be overkill, and use unnecessary power. Bit of overkill.

Thanks again

Ben


I';m about to play with a couple of washing machine motors so I will have more to say about these soon.

[malb]

What does the machine currently use for a motor and controller?

I suspect something similar to a sewing machine motor and pedal judging from the mention of a control pedal. If it is something in that order, you could possibly use a 400W or higher lamp dimmer and an on/off footswitch with the current motor. Then the dimmer unit can be mounted in a box so the billylids cannot easily the speed knob, but you can still access it occasionally for setup/adjustment while they are out playing footy, taking nature walks etc and can't watch and learn how you get to the speed control.

If the motor is more powerful than the typical sewing machine unit, but is a variable speed capable universal (brushed) motor, you can get stand alone variable speed controls for power drills and other and tools as kits or possibly as completed units and do basically the same thing (controller and on/off pedal switch).

Edit.

Just found your earlier post, where you mention using a DC motor and speed controller, rather than an AC unit, and mention the possibility of switching between two or three fixed speeds. The same concept outlined above, using the existing control module and motor and an on/off pedal (or other style) switch. Multiple switched speeds could be achieved by adding a speed selection switch and using that and variable resistors to set the speed.

[zongatron]

Awesome,

thanks guys. And I thought this was going to be simple - buy a motor, plug it in and spin away! Of course not.

I am going to ask a "motor rewinder" on Monday if he ccould come up with something - to try and get somewhere as I need to fast track the project as I already have a gig lined up.

I will print out these suggestions and take them with me.

Do you guys think that's who I should be seeing? Or should I just ring my friendly neighborhood electrician to see if he is interested in wiring a few of these up etc?


Ben

[BobL]

Awesome,
thanks guys. And I thought this was going to be simple - buy a motor, plug it in and spin away! Of course not.
I am going to ask a "motor rewinder" on Monday if he ccould come up with something - to try and get somewhere as I need to fast track the project as I already have a gig lined up.
I will print out these suggestions and take them with me.
Do you guys think that's who I should be seeing? Or should I just ring my friendly neighborhood electrician to see if he is interested in wiring a few of these up etc?
Most neighbourhood electricians won't (with some reason) work with second hand gear, won't know much about motors and will naturally recommend a solution that suits them.
A motor rewinder is likely to be more knowledgable but is also likely to recommend "new product" solutions.

I've just been messing with two washing machine motors and they seem like they would be ideal.
Both are 1440 rpm motors.
One is cap start and draws 0.6A free running while the other is a switched start motor that draws 1.5A

Somewhere I have a dimmer switch that I will try on the cap start motor and I'll see what happens.

[zongatron]

Great Bob,

I await eagerly!

Although I must confess I know next to nothing about motors volts and amps. Cap starts etc. I have tried to make some sense of it here online but get confused very easily.

Thanks again

Ben

p.s. I did just learn a little about a cap start motor on wiki. That is interesting

[BobL]

I found the dimmer and hooked it up to the washing machine motor and it's a bit of a dud.

It works sort of between about 1440 to ~1250 RPM but below that the motor has increasingly limited power to the point when I can stop it running by hand at about 1150 rom and it stalls completely at about 1050 rpm.

I've noticed this before on fan motors but the RPM range seems to vary with the dimmer.

It can't be the motor being two powerful as it is only drawing about 125W

[zongatron]

Hi Bob

Is there any reason why I would want a dc motor and not an ac motor?

Do AC motors need some type of cooling fan or something?

Do you think this would work? -

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=111323102722&fromMakeTrack=true&ssPageName=VIP:watchlink:en

with this controller?

http://www.ebay.com.au/itm/1-5KW-2HP-single-to-3-phase-VFD-Freq-upto-400Hz-Motor-speed-VSD-/281312330152?pt=AU_B_I_Electrical_Test_Equipment&hash=item417f8581a8&_uhb=1


If I could get away with 900rpm, i wouldnt even need a vfd with this motor would I? Just an on and off switch?

I would be more than happy spending about three hundred on each motor.

The last person I spoke to said I wouldnt get anything speed controlled for less than $1500 each.

Thanks

Ben

p.s. Just lastly, I was reaidng a previous post and he had water issues.

The VFD is not a good look for what I am doing. Can I mount the VFD away in a box, and have separate on off switches to use on the actual unit?

[BobL]

Hi Bob
Is there any reason why I would want a dc motor and not an ac motor?
Do AC motors need some type of cooling fan or something?
DC motors generally have a much wider speed range with the same power across the speed range than AC motors.
But this sounds like it's irrelevant to your needs.


Do you think this would work? -
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=111323102722&fromMakeTrack=true&ssPageName=VIP:watchlink:en
with this controller?
http://www.ebay.com.au/itm/1-5KW-2HP-single-to-3-phase-VFD-Freq-upto-400Hz-Motor-speed-VSD-/281312330152?pt=AU_B_I_Electrical_Test_Equipment&hash=item417f8581a8&_uhb=1
Yep - the motor is 240V 3Phase Delta capable so that would work - the prices are good but I have no idea what a sparky would charge to wire it up.


If I could get away with 900rpm, i wouldnt even need a vfd with this motor would I? Just an on and off switch?
Nope - you will need the VFD because it is s 3phase motor and unless you have 3 phase sockets where you are operating you will need the VFD to convert 240V single to 240V 3 Phase.


I would be more than happy spending about three hundred on each motor.
The last person I spoke to said I wouldnt get anything speed controlled for less than $1500 each.
:(( Maybe he was a sparky?

[zongatron]

Hi Bob,

Would this VFD work with this motor?

http://www.ebay.com.au/itm/2200W-3Hp-240V-10A-Single-Three-Phase-Variable-Frequency-Drive-Inverter-VFD-/390815072128?pt=AU_HeavyMachinery&hash=item5afe64bf80&_uhb=1



http://www.ebay.com.au/itm/111323102722?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Thanks mate.

Ben

[BobL]

Hi Bob,

Would this VFD work with this motor?

http://www.ebay.com.au/itm/2200W-3Hp-240V-10A-Single-Three-Phase-Variable-Frequency-Drive-Inverter-VFD-/390815072128?pt=AU_HeavyMachinery&hash=item5afe64bf80&_uhb=1

http://www.ebay.com.au/itm/111323102722?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Thanks mate.

Ben

Yes it would but it is overkill to use such a high power VFD on such a small motor. You are better off getting a smaller one.

BTW I tried out an old school (500W) versus near new (400W) Light dimmer on a washing machine motor this arvo - same problem.

[jhovel]

This would like a better deal so far: http://www.ebay.com.au/itm/291127571936
but you can also scale down and save a bit with this VDF: http://www.ebay.com.au/itm/221229448192 which is still overkill...

If I may make a suggestion: det a heater fan motor from the local wreckers and a wire-wound rheostat (potentiometer) of similar (or higher) power to the motor you find and connect them to a 12V powersource of some kind (of adequate power). I think that would do your job easily!
You could try it out without the rheostat first and see if it's fast enough and measure how many amps it actually uses under your load, then get the rheostat and powersupply to uit (maybe a cheap transformer battery charger, for example). To just try it, use your car battery. The whole exercise would cost heaps less and be much easier to install.... and no concern for water ingress etc. 12V wont hurt you if it all goes pearshape at some point (like you drop your paint bucket in it :o )...

If you dislike using secondhand gear, have a look here: http://secure.oatleyelectronics.com//product_info.php?products_id=1060
A new suitable power supply for this combo would be $25.47 from here: http://www.ebay.com.au/itm/350865972144

[BobL]

I'd feel much happier about you using the 12V options as suggested by Joe. Much safer and simpler and a lot cheaper by the looks.

[zongatron]

I thank you all again.

I think i am finally coming to grips with my options.

It is very overwhelming trying to work out electric motors with little to no knowledge about them or electricity, and it seems I was misled by my first phone enquiry, whom told me i would not get anything speed controlled for under $1500.00.
Since then I have been trying to problem solve a problem that is not really there.

You guys have helped me get close enough to be confident when talking to my electrician.

1) This is going to be used at schools and fetes etc, it will have an awful lot of use so im thinking something a little more industrial would be better.

2) I need to mount a pulley onto the shaft (onto which I can mate some chequerplate on which to mount a canvas) and cant seem to find a pulley under 12mm, So shaft size is important.

Where Im at now -

If i simply buy a .18kw 3 phase 4 pole engine (for around $90) then buy the appropriate VFD ( for around $100-150) I will have a speed controlled electric engine with decent sized shaft diameter that should easily turn the load of about 400grams.
I have found an electrical engineer who has said he will wire it all up for me no problem.
He is even trying to source the motor and VFD for me.

The only uncertainty is if it will run slow enough for me at around 300rpm,
One person told me it should give you a complete range of speed from 0 to upwards of 1440. While another said it might not go slower than 500rpm as the motor still needs to kick...)


So I am very happy with the outcome so far as I can afford that combination.

And if a 4 pole motor wont run at less than 500 rpm, I can always trial a 6 pole I guess.

I trialled a single phase at 1440 and it was way too fast.

I need about 300 up to 1440 rpm

I will let you know how it goes.

Thanks again everyone, and you Bob.

Ben

[jhovel]

A 0.18kW motor driven by a VFD at 300rpm will have enough power to spin 1/2 ton! let alone 400g. In terms of cost and complexity, its way over the top.
The (completely sealed by the way) DC motor I suggested from Oatleys is 0.1kW, and 0.2kW is the allowed motor size for electric bicycles and they go uphill with a fat human sitting on top of it - that's just to give you an idea how much power we are talking about. I have one of the Oatley 12V motors in my wife's felt rolling machine. It's been going pretty well continuously for 6 to 8 hrs a day for the past 4 years.... so no worries about sturdy or longeivty there either.

If you are going to use a pulley, you can easily change the maximum speed of the whole setup anyway: if you put a 120mm diameter pulley on the wheel and a 30mm pulley on the motor, your speed is reduced by 1/4 - and your torque (turning force) quadupled. Then you will be able to spin an elephant at 300 rpm with your 0.18kW motor :)

[zongatron]

Okay,

Thank you for clearing all that up.

Yes .18kw seems over the top now.

But, how do I control the speed on the dc motors? I need to be able to set it and walk away. Then come back and set it at another speed and walk away etc. (The dials on VFD would be good for this.)
Could I simply use this?

http://www.banggood.com/PWM-DC-Motor-Speed-Control-Controller-Switch-Regulator-p-912616.html?currency=AUD&utm_source=google&utm_medium=shopping&utm_content=miko_ruby&utm_campaign=electronic-zeng-au&gclid=CPyHqfeahL4CFVEIvAodXpIALg

or this

http://www.ebay.com.au/itm/FAN-SPEED-CONTROLLER-HIGH-TO-LOW-DIAL-NOZZLE-3-SWITCH-VARIABLE-OFF-FULL-/151267491849?pt=AU_Seed_Starting_Hydroponics&hash=item23383ec009&_uhb=1

And does that power converter mean I can simply plug it into the powerpoint?

I am not sure that I can mount a frame to this motor.

The frame itself will be 30cm x 40cm chequerplate square that I want to mount directly to the motor shaft. This is what the canvas would sit on.

Any ideas on that?

Thanks very much.

Ben

( Just when I thought I had it all sorted out! haha)

[jhovel]

Mmmm - you might have to re-read my previous posts.
The banggood speed controller is fine with a 24V DC motor. But why? The Oatley motor comes with the speed controller?
The second one is for 240V AC appliances - so it would blow up the 24V motor. You woould be better off to stick with the speed controller I recommended to buy WITH the motor.
You DO need a suitable 24VDC powersupply which connects to the powerpoint (240VAC and converts that to 24V DC - you need at least 4A current output, because 24V x 4A = 96W).
The Banggod speed controller and the one I recommended are both set and walk away and you change them by turning a dial..... Oh. I just noticed the Oatley speed controller needs a potentiometer and a resistor in addition to set the speed. Your electrical friend can connect that - as can you, since it comes with instructions - or we can help you by 'remote control'.

Mounting the platter is a matter of making or having made a flange with the right inside diameter and some mouting holes for the platter and a grub screw to hold it to the shaft. The motor has 4 threaded holes in the end plates to bolt it to a support frame or plate. Like you woould have to do for any motor you might choose.

[BobL]

. . .Mounting the platter is a matter of making or having made a flange with the right inside diameter and some mouting holes for the platter and a grub screw to hold it to the shaft. The motor has 4 threaded holes in the end plates to bolt it to a support frame or plate. Like you woould have to do for any motor you might choose.


To mount the platter on the motor will require the assistance of someone with a metal work lathe.
I note that you want to use a 40 x 30 cm platter - this will make it harder to balance than if it is circular.
If it is not balanced it will wobble the motor and art work like a feral supermarket trolley wheel and could even be dangerous.

The way I would do it is to get the flange turned up or fabricated with an alignment collar on the outside. Drill a hole on the platter to suit the alignment hole on the flange and then and attach the platter to the flange with screws. Once the platter is attached put the flange back into the metal work lathe and turn the platter circular with the lathe. That way it will be very close to being balanced.
This is how I make larger diameter pulleys and it seems to work well.
http://www.woodworkforums.com/attachment.php?attachmentid=312016&stc=1

[zongatron]

Hi again,

I just wanted to give you all an update on the spin machines.

I have completed several machines now and they work fantastic.

I went with the .18kw electric motor and the VFD and am very happy I did so.

The units all have heavy duty switches etc and run very smoothly.

As the .18kw motors are quite large it made it easy to mount a plate. The 11mm spindle takes a pulley, and then a plate is simply screwed to the pulley.

The DC motors sounded fine but the amount of wiring was starting to add up with all the bits you need etc. If I had the confidence to wire all that up myself i suppose I could have done it, but then there were insurance issues as I will be using these with the public.

In any case, they run from zero rpm's all the way up to top speed with the simple turn of a dial.

Can anybody tell me how much current these draw? Is it simply a maximum of 180 watts? (.18kw) depending on load etc?

If anybody wants photos of the finished product send me your email and I will send you some. They boxes all came up quite nice.

Ben

[BobL]

Good to hear it's working out.
Please post some pics of the art here.

180W will be a nominal max load power.
If the motor is just spinning chances are it will be using MUCH less than this.

[zongatron]

Good to hear it's working out.
Please post some pics of the art here.

180W will be a nominal max load power.
If the motor is just spinning chances are it will be using MUCH less than this.

hi

Dont know if the photos worked.
Couldnt really work out the photo manager etc

ben