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Does a 1600rpm bantam have a single v belt?

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Mark Davison 114/04/2019 20:49:26
79 forum posts
36 photos

Does anyone know if the 2 speed / 1600 rpm Colchester Bantam came with a single or double V belt. I'm about to fit a 2 hp 230v 3 phase motor/VFD in place of my single phase 1hp motor (800rpm machine with a single belt). I would have gone for 3hp but I got an old but unused 2hp cast iron Brook Crompton for a really good price).

Manual seems to suggest it is only a single pulley.

Emgee14/04/2019 21:14:18
1541 forum posts
219 photos

Single belt on mine, a 1996 model.


Emgee14/04/2019 22:29:09
1541 forum posts
219 photos

Correction, should be 1966 model, GB World Cup winning year.


Falco14/04/2019 22:42:28
65 forum posts
7 photos

Mine has a single belt also. 1967 model if memory serves me right. J


Pete Rimmer14/04/2019 23:54:48
734 forum posts
50 photos

I put a 3hp motor on a Bantam with a single belt and ran it up to 1600rpm on the VFD no problem at all.

Mark Davison 115/04/2019 06:10:25
79 forum posts
36 photos

Thanks everyone

Niels Abildgaard15/04/2019 06:29:13
310 forum posts
116 photos
I got an old but unused 2hp cast iron Brook Crompton for a really good price).

I found two old motors and they smellt very bad being VFD-ed.

I then bought a new and total happines.

How old is the motor?

Mark Davison 115/04/2019 06:51:07
79 forum posts
36 photos

Not sure, don't recall seeing a date on the data plate. They (i bought two) are 90 frame as opposed to imperial, with moulded plastic fans and fan shrouds. Dual voltage as standard. Saw it run on a 400v rotary converter before I bought it and all seemed well. Nothing ventured nothing gained. Worst case I have to cough up for a new one, which is what i had previously intended to do anyway.

Clive Foster15/04/2019 11:08:36
2245 forum posts
73 photos


I think its safe to say that any dual voltage Brook Crompton motor modern enough to be a 90 or other post imperial frame size will be perfectly happy running on an inverter. Especially if you stick to the old conservative ± 1/3 rd of data plate speed range. No cooling fan issues, no significant torque loss at lower speed issues (in home shop use anyway) and no odd internal electrical / magnetic interactions to upset things. Although the latter is more likely with a budget "count the turns near enough" re-wind. These things were designed to run on nice 50 or 60 hz sine waves using, by modern standards, pretty basic formulae so no sense in pushing the envelope.

In your position I'd seriously consider altering the pulley sizes to lower the gearing a little and make better use of the high speed end of the inverter drive range. Take a good look at the speeds you tend to use and try to set the gearing to minimise gear changing.

(Not an inverter I know but the high speed range of Reeves varispeed drive on my S&B 1024 often drives me nuts because bottom direct drive speed is 330 rpm or so when 200 or thereabouts would avoid a lot of switching in and out of back gear. I'd never miss the difference between 2400 and 2200 at the top.)


Edited By Clive Foster on 15/04/2019 11:09:09

Edited By Clive Foster on 15/04/2019 11:09:32

Edited By Clive Foster on 15/04/2019 11:09:55

Mark Davison 115/04/2019 19:05:33
79 forum posts
36 photos

I'm primarily interested in getting access to speeds above 800rpm which is the max with the current single phase motor. The low speed is fine. At the moment I've order exactly the same size pulley, but may also order a slightly larger one as (I think ) you're suggesting

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