33 replies to this topic

[Maxim]

Hello All!

I have been seeking sources to buy equipment in order to construct my own star rolling machine.

I am aware that i need a 60RPM motor and for it to be completely sealed.

@PhilDunford - I am the guy at the AGM who asked you whether you could provide the plans so here i am again!

[Arthur Brown]

The RS catalogue lists lots of motors some AC some DC some universal. Some are sealed enough and already have gearboxes attached. Rapidonline, and several other dealers will have similar lines. These will be new and cost serious money. Otherwise look on ebay and as many electronics surplus shops as you can find.

[Maxim]

Thanks! Ye i am on a budget so what kind of motor should i look for in terms of specs?

I understand so far the specs should be AC or DC 60RPM, sealed. What about torque values?

[Maxim]

What would you say about something like this?

http://cgi.ebay.co.u...=item335bdec646

[phildunford]

Hi Maxim!

Nice to hear from you again...

I will try and put some details up soonest, but I have about three projects on the go at the moment!

Although a totally sealed motor is one way to go mostly people separate the motor from powder by some means. In mine it's in the housing and the bearing is a pretty effective barrier to dust.

As to speed, it's not a particular RPM you need, you need to be able to vary the speed so the stars flow nicely, so you will need some sort of speed controller. Mine uses a simple PWM circuit, but there are a lot of ways to do it... More details to follow!

[Maxim]

You are a very busy man Phil, take your time

[Arthur Brown]

Remember also that the output shaft on a motor though able to deliver the torque may NOT be able to support the radial load from the drum and contents.

[Maxim]

Do you own a star roller Arthur? If so, was your motor expensive? If not, would you be able to provide details?

[Arthur Brown]

No I don't, (sadly)! I used to have lots of sources of "useful" things, but less so now. Search ebay for "Parvalux" they are great makers of great motor gearbox units. You may find something suitable and robust.

[phildunford]

The parvalux units are indeed excellent - I use one on my ball mill. However in this there is pretty much an ideal speed and you can arrange a drive chain to get it right.

See here ball mill

For a star roller, you really need variable speed. I think you sometimes get the Parvalux units with DC motors, but they are mostly AC. In this case you would need a different speed controller. If they are AC universal motors you could use a drill speed control, if they are induction, you would need a variable frequency inverter, which could get a bit pricey...

An idea I've just had, but not tried would be to buy a cheap battery powered drill and use the bits from that... Plenty of guts I would think and a DC motor and you can get them pretty cheap from places like Screwfix and CPC. They also usually have a speed control on the trigger. Just a thought.

[Arthur Brown]

Parvalux do make motorgearbox units with low volts, mains 230, and mains three phase supplies. The also make universal AC/DC motors which will easily take a speed controller (mains on the field winding phase angle chopped mains on the armature winding. There are so many motors and so many gearboxes that waiting for the right on on ebay may be time consuming!

WC71N is a small DC motor from Maplin that will cover the required speed range using even just a switchable DC wall wart, (better with an adjustable PSU!) This will certainly turn the drum you want BUT how long the bearings will support the bowl full of stars, who knows. likewise N03BQ a bit bigger a bit more expensive.

Maybe it would be better to get a bearing block and shaft to hold the drum and then a motor and pulleys to turn the shaft at the required rate.

On a mains motor TEFC means totally enclosed fan cooled and is good, Shaded pole means no contacts in the mechanism so that's good too. Brush motors -that's all DC and Universal- will have brushes and hence sparks inside. They will need a good case and maybe a fan too.

Edited by Arthur Brown, 17 April 2010 - 08:24 PM.

[Maxim]

Thanks so much for your help! It is very much appreciated! You dont get many people as kind and helpful as you guys nowadays!

Ive had a look around and the only thing that ive found that is both cheap and sounds right is this:

http://cpc.farnell.c...4-4v/dp/TL12706

What are your opinions on the matter? I've gone for Phils idea of using a drill.

[Arthur Brown]

With a no-load speed of 550 rpm it's going to be hard to have choice of controllable speed in the region of 40 - 60 rpm especially as the trigger will be behind the star drum, unless you are going to make a (foot operated? ) remote control.

Unless you bodge it badly it will still be a useful drill for DIY.

[Maxim]

Well i mean the other drills ive seen cost more than £80, mainly even over £100 which is, im afraid, a bit over budget!

[digger]

Keep looking on ebay, bargains do come up.

Motor and speed controller combo's do come up. I have bought two 1/2 hp motors with controllers for less than £40 each.

Don't forget you do not have to have a direct drive for your star roller. You can always use a pulley system to reduce the speed.

The best sort of motor for this application is an ATEX rated motor. However I guess these don't really come up on ebay. ATEX stand for atmospheres explosive and they are specifically designed for various applications (Zone 0 is required, possibly zone 1 if the design allows)

I would avoid a hand drill on three counts. First the motors spark like buggery, secondly you will find they have very little torque and thirdly the last thing you want is battery power in this app as it will run down far two quickly with continuous use.