Parvalux motor – help please

[Mike WaldronParticipant @mikewaldron61652]

Hi

I have a Parvalux motor attached to my Marshall Watchmaker’s lathe, which bears a most uninformative specification plate.

 

Surely this is not a 75rpm motor??

……..and there’s no fractional HP rating

Does anyone else have a similarly useless plate on theirs?

 

Or perhaps it is a Friday job…

Mike

 

[duncan webster 1Participant @duncanwebster1]

Lots of parvalux motors were sold with a worm gearbox fitted, and the plate gives the output speed of the gearbox. Taking the gearbox off is dead easy, leaving a normal speed motor (probably 1500 rpm nominal) , which is what I had on my little perris lathe.

[peak4Participant @peak4]

I’m guessing it was originally fitted to one of their proprietary gearboxes, with a fixed reduction ratio, to give a 75rpm final output.
I have something similar, but don’t recall the make offhand.

Bill

[noel shelleyParticipant @noelshelley55608]

I ‘m with the others, it is the output of the wormdrive box NOT the motor. I have a similar unit in the shed. Noel.

[Michael GilliganParticipant @michaelgilligan61133]

Strangely … SD9 doesn’t seem to feature on the current Parvalux website:

https://www.parvalux.com/

… but it’s worth browsing, to see their wide range of products.

MichaelG.

[mark smith 20Participant @marksmith20]

Theres a similar one on ebay but single phase  also with no HP details.But SD9.

https://www.ebay.co.uk/itm/235822219648?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D275254%2C276749%2C276105%26meid%3Decb0cd1d776540d19cc89d00e293ff8a%26pid%3D101224%26rk%3D2%26rkt%3D5%26sd%3D146152092975%26itm%3D235822219648%26pmt%3D0%26noa%3D1%26pg%3D2332490%26algv%3DDefaultOrganicWebV9BertRefreshRankerWithCassiniEmbRecall&_trksid=p2332490.c101224.m-1

 

[Ian PParticipant @ianp]

That Parvalux motor is also unusual in being wound (or rated for) 220 and 380VAC. Because of its current application driving a watchmakers lathe I presume it is single phase although it is possible that if it was part of some industrial equipment a transformer might have been incorporated. The plate then showing the system rating just like the speed and the torque value (too high to be the motor spindle).

Ian P

[not done it yetParticipant @notdoneityet]

Help yourself?  Their telephone number is 01189 733337

[not done it yet]

On not done it yet Said:

Help yourself?  Their telephone number is 01189 733337

Well that’s a thread stopper!

No need for this forum, anyone with a problem can just find the manufacturers phone number and get help direct.

Ian P

[Mike WaldronParticipant @mikewaldron61652]

Thanks all

As the lathe was old, I was under the impression that Parvalux were obsolete, so assumed that I’d need to contact people who knew.

I have since sent a message with a photo to Parvalux to ask for more details.

 

Thanks all

Mike

[Trevor Drabble 1Participant @trevordrabble1]

1. I have an illustrated 1999 Parvalux catalogue which shows a 75rpm SD8  gearbox unit, which is rated at 35 watts. Wonder if the SD9 is a later iteration of this unit ?

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, you can download this Parvalux catalogue 2007 but, the O/P’s motor is much older, and the 2007 one is the earliest one in their archive list.

Regards Nick.

[EmgeeParticipant @emgee]

I have some spare Parvalux FHP motors with or without gearbox if you need a replacement, all 230vAC working.

 

Emgee

[Andrew TinsleyParticipant @andrewtinsley63637]

I have found Parvalux to be extremely helpful in answering telephone queries. I contacted them a few years ago and they even sent me details of their old motors FOC, which were no longer in production.

I don’t want to get involved in the above spat. Just saying how helpful Parvalux was. Made a refreshing change.

Andrew

[Ian P]

On Ian P Said:

On not done it yet Said:

Help yourself?  Their telephone number is 01189 733337

Well that’s a thread stopper!

No need for this forum, anyone with a problem can just find the manufacturers phone number and get help direct.

Ian P

Ringing firms up and asking for information is worth a try, but don’t expect an answer!   My day job once had a responsibility for answering queries. Historical questions were often too expensive to answer because they required a paper archive on a remote site to be opened up and searched.   About 3-4 hours work, thirty years ago, costing a couple of hundred quid.   Later, the organisation decided there was very little value in answering casual interest queries and laid down strict rules for anything costing more than £30. Enquiries were discouraged unless they were from a serious source. Parvalux might be happy to explain an obsolete motor if the information happens to be at hand, but I fear they’ll decline the offer.  Unless of course a customer rings up wanting to buy a thousand new ones…

Other than the mystery of the plate information, I don’t think Mike has a problem with the motor?  Presumably it works OK.

I think the plate seems peculiar because the motor was originally supplied with a reduction gearbox.  Therefore the plate tells us what the output shaft does:  75rpm with a Torque of 14 pounds per inch.   I don’t think the plate is a Friday job, it just relates to the motor/gearboxes original application, where the currency is torque, not power.

14 lbf/in is about 2.5Nm (Newton Metres) and it was delivered at 75rpm.   This online calculator suggests that equates to an output power of about 20W, which seems low to me, but maybe the worm drive was exceptionally inefficient.   Assuming the worm was 50% efficient, then the motor output needed to turn it would be about 30W, roughly 36W input.   However, the motor is rated to deliver that torque through the gearbox continuously, so maybe double or triple the estimated motor power to perhaps 100W input, roughly ⅛HP, which seems reasonable for a watchmakers lathe.

Dave

 

 

[Ian PParticipant @ianp]

Why do you think the motor plate shows 220 and 380 volts, seems unusual for a such a small motor. The one on ebay seemed to have several capacitors with it, maybe it uses one as a capacitive dropper and another for phase shift.

Maybe Mike will let us know how its wired or when Parvalux reply.

Worm (we are assuming here) reduction gearing must be about 20:1 to get the 75rpm.

Mike told us that he uses it with a watchmaking lathe, its probably not its original application.

 

Ian P

[Ian P]

On Ian P Said:

Why do you think the motor plate shows 220 and 380 volts, seems unusual for a such a small motor. The one on ebay seemed to have several capacitors with it, maybe it uses one as a capacitive dropper and another for phase shift.

Maybe Mike will let us know how its wired or when Parvalux reply.

Worm (we are assuming here) reduction gearing must be about 20:1 to get the 75rpm.

Mike told us that he uses it with a watchmaking lathe, its probably not its original application.

 

Ian P

The SD8 frame size motors are available in both single & 3 phase; the latter might well be marked as dual voltage.
Single phase motors often have a capacitor as a permanent run, one of mind does; see the 2007 catalogue.
Similarly a 3 phase motor can be made to run on single, with the addition of one or more capacitors, depending on the starting torque requirement.
The presence of a capacitor may well be misleading, if a previous owner has re-purposed a 3 phase motor, wired as delta, and added a phase shift run capacitor across one of the windings.
The clue might well be in the wiring colours, and/or the coil resistances.

Bill

[Mike WaldronParticipant @mikewaldron61652]

Ian P

the wiring is basically a mess! The previous owner has somehow run wires across the board the lathe is mounted on, to external (non original) capacitors, and an on/off and a reversing switch!!

Goodness knows why a reversing switch is needed, there’s no screwcutting gear!

The visible wires are all green, so no help there.

My intention is to strip it back to basics, and remove a strange countershaft, which seizes up in cold weather – thereby sapping power from the motor. So it’s either that or to mount a new 180 Watt sewing machine motor, which is much smaller.

Mike

 

 

[duncan webster 1Participant @duncanwebster1]

I’m with peak 4, I reckon it’s a three phase motor with a Steinmetz connection to make it run off single phase. How to wire it up is covered in the workshop practice book on electric motors.

It seems like a bodge, but I’ve successfully done it on a grinder. You can’t get full power, but not far off.

[Michael GilliganParticipant @michaelgilligan61133]

It will require a leap of Faith/Imagination, but as these are the only connection diagrams for the present range of 3-Phase SD motors, they might help Mike interpret his Spaghetti wiring:

.

.

 

Ref.

https://www.parvalux.com/app/uploads/2021/03/Parvalux_-_AC_Catalogue.pdf

 

[Mike WaldronParticipant @mikewaldron61652]

Hi All who have had some input to this thread:

I have made an interesting discovery today, when removing the countershaft from the back of the Marshall lathe.

I’ve always suspected it was a DIY job, and the answer is that it has proved to be the original Parvalux worm gearbox converted into a countershaft!

Somewhere in the scheme of things, the worm has been removed, and the wooden pulley cone has been fitted on to the gearbox shaft – not sure quite how. There are four ‘pins’ in the small end of the cone, so I appears that they are dowels of some kind. The bore at the end of that cone appears to in the order of 8.7mm – though I suspect it should be an Imperial size, as Marshall’s were made in the USA.

The aluminium pulley has come off using a 1/8” Allen key, and itself has two very different diameter pulleys – 1 1/2” and 3”.

Clever…. Or awkward, as it seemed to add more potential friction for the motor to overcome, especially in cold weather! Like now!

Besides, the maximum diameter of metal I am likely to be using will be 1/4” or 6mm, or delicate castings of the wheels I will need to turn down to put steel tyres on, so I don;t think a countershaft will actually be needed.

But those steel tyres will need to be turned with my form tool on the ML7

Mike

[Michael GilliganParticipant @michaelgilligan61133]

Devious repurposing !

Thanks for sharing the details.

MichaelG.

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