Parvalux motor

This topic has 11 replies, 6 voices, and was last updated 4 June 2019 at 11:46 by Mick Henshall.

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3 June 2019 at 20:30 #412444
Mick Henshall
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@mickhenshall99321
I have a motor with following specs

12 volt dc max amps 6 watts output 45 rpm 3000

Rating continuous gearbox spec NM5.3 RPM 50

I already use one of these to power a mechanical hacksaw which is slow but does the job, question is would this motor have enough torque to run a handheld portable bandsaw? I am trying to build one using a 45" length blade with 10/14 tpi mainly to cut ferrous and non ferrous metals, blade speed would be around 180 ftpm, the torque is my main concern, any advice would be appreciated

Thanks Mick 🇬🇧
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3 June 2019 at 20:30 #13541
Mick Henshall
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@mickhenshall99321
3 June 2019 at 20:51 #412446
Neil Wyatt
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@neilwyatt
Six watts is a bit puny, to say the least. An Aldi bandsaw is 350 watts.

To get the blade to move at 100 feet per minute (low end) you will need a pulley with circumference 100/45=2.2 feet, that's 0.35 feet radius, say 100mm.

5Nm on a 100mm radius pulley will give you 50 newtons force at the rim, that's 5kg of pull. I think you need much more than that.

Neil
3 June 2019 at 21:23 #412453
Mick Henshall
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@mickhenshall99321
Thanks Neil doesn't sound too hopeful, I do have a 240 ac motor with 2800 rpm maybe I could take the gearbox from the Parvalux and adapt it to fit the ac motor

Mick 🇬🇧
3 June 2019 at 21:33 #412457
Frances IoM
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@francesiom58905
the current 6A would indicate more than 6 watts possibly nearer 70W – however taking the gearbox apart might not be that easy as worm is pinned to the motor drive shaft very close to where the shaft emerges and I suspect you would need to reduce the motor shaft diameter or live with a long extension (its also very messy as packed with grease)
3 June 2019 at 21:50 #412460
Mick Henshall
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@mickhenshall99321
I have just found an Armstong ac motor with 2800 rpm and is 0.7 hp, problem is reducing rpm adapting gearbox still an option Frances but I take your points, I have some 1425 rpm motors, gonna have to ponder this maybe make a gearbox or use pulleys, nothing is easy is it but nothing ventured

Thanks Mick 🇬🇧
3 June 2019 at 21:55 #412461
SillyOldDuffer
Moderator
@sillyoldduffer
In line with Frances, I read it as:
- 12 volt dc
- max amps 6
- watts output 45
- rpm 3000
I guess 45W is continuous, with up to 72W input peak. Still weedy for a bandsaw, but you could drop the blade speed and let the motor take its time.

Dave

Edited By SillyOldDuffer on 03/06/2019 21:55:48
3 June 2019 at 22:11 #412465
Mick Henshall
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@mickhenshall99321
Clutching at straws I have seen on YT a home made hand held bandsaw driven by a battery drill, seemed to cut through light section steel sections fine which is all I want to do, I don't want to part with £300-£400 for a commercial one and I like the challenge of making one if it works then great if it don't I'll stick a higher rpm motor on it and use it for woodwork

Thanks gents

Mick🇬🇧
3 June 2019 at 23:10 #412472
Neil Wyatt
Moderator
@neilwyatt
Posted by Frances IoM on 03/06/2019 21:33:43:
the current 6A would indicate more than 6 watts possibly nearer 70W – however taking the gearbox apart might not be that easy as worm is pinned to the motor drive shaft very close to where the shaft emerges and I suspect you would need to reduce the motor shaft diameter or live with a long extension (its also very messy as packed with grease)

Ah misread it as 6 Watts.
4 June 2019 at 08:53 #412500
Clive Foster
Participant
@clivefoster55965
Mick

If you do decide to use pulleys to reduce the speed 4 poly-Vee pulleys arranged in the same configuration as lathe back gear can give high reduction in compact space. Compared to ordinary V belt pulleys poly-Vee ones can be much smaller diameter. The drive one on my tumble drier is little more than an inch in diameter yet transmits considerable power!

You don't actually have to make the output shaft and motor shaft concentric. If the motor is of conventional construction with through studs extending the studs with suitable spacers and adding plates to carry the bearings makes for avery compact construction. I have done similar myself albeit with the output shaft offset. Doesn't seem unreasonably difficult to use one of the carrier plates as part of the bandsaw bow.

Clive

Edited By Clive Foster on 04/06/2019 08:55:24
4 June 2019 at 11:21 #412527
duncan webster 1
Participant
@duncanwebster1
There is some info relating metal removal rate to power at **LINK**

This is for turning, not sawing, but it's a start. Quick sum shows that even if all the power was available at the blade, it will be be terrible slow for cutting decent size bar
4 June 2019 at 11:46 #412530
Mick Henshall
Participant
@mickhenshall99321
Some interesting comments gents for which I thank you,having thought overnight (funny how things keep you awake)

I am thinking of using my Adcock & Shipley horizontal mill as the driving source,it has a 1Hp motor it has 15 speeds the lowest being 60 rpm, yet to decide to drive with a pulley on the arbor or from the spindle direct,there are also some work clearance issues to sort.Food food for thought.

Interesting comments Clive/Duncan

Mick🇬🇧
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