I have a big problem to work out,I am about to buy a vapormatt bead blaster that needs 20 cfm to work correctly,to get this type of output there seem to be a couple of options when using 240v,first is to run two 3hp compressors in tandem or a larger 3 phase one with the help of a converter box from transwave, has anyone out there had experiance of these converter boxes on a 3 phase compressor,any help gratefully recieved.
- Thread starter fastharry
- Start date
dont know the HP for 20 Cu ft, but converting single to 3 phase is gonna cost you a bomb, I have a 415 3 phase - 71/2 Hp -- nearly a grand, dont know if it would run a compressor though, Machine cutting in and out all the time, And I have to be carefull about the consumer supply, I dont run my compressor and my 71/2 Hp together, probably pull too many amps and blow or trip something.
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Speak to Dave at Drives Direct
General Information
Please contact us using the details below.
Tel: 01623 720730 Fax: 01623 720710 Mobile: 07976 766538
Email: info@drivesdirect.co.uk
Drives Direct(Inverters) Ltd
Unit 1, Phase 2(Behind TTS)
Park Lane Business Park,
Park Lane
Kirkby In Ashfield
Nottingham
NG17 9LE
http://www.drivesdirect.co.uk/index.html
always done me proud and no complaints.
Stan
brightspark
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static converters are no good on compressors rotary cost a mint for that size 2 3hp single pumps would be your best option. i run one. one other point u do not get full power out of a static converter so a 1hp motor will end up putting out about 3/4 hp
penfold
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No use is a bit pejorative, but motors running off them do lack starting torque.
brightspark
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take it from me i have one myself and fitted 3 others for other people . one on a 4 poster lift that was suposed to be fit for purpose and couldnt lift the vehicle at its full capacity
and they dont have the starting torque under load .
gordon stephenson
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My lad has a static converter running his 4 post lift,No way will it start under load, You have to give the coupling a couple of turns in the opposite direction to give it a run at it,
brightspark
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u can hardly do that with a compressor cutting in and out
I can only afford second hand compressors,i can get 2 small hydrovanes for a grand, large three phase ones seem to be cheap at around £300, a new converter is about £600 for the size i want,so not much in it,apart from not knowing for sure if the converter can actually pull the motor in when the pressure switch kicks in and it will still have air in the tank,a copressor guy i spoke to didnt think it would cope with a half full compressor,??
rtbcomp
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The pressure in the pump is released by a valve in the pressure switch when the pump cuts out, so it shouldn't make any difference how much air is in the tank.
Mines reasonably likely to trip the rcd when tank is full or near full. It does blow off when shut down.
Initial movement of the piston creates pressure, when tanks empty its easy to startup. The current draw can be higher than 16A on a 240V single ph 2.25kw cap start.
Likewise on another machine my 2.25kw 3ph 400V needs at least 7.5kw just on low gearing, no way can i approach normal speeds from stationary and thats best part of £1100. My 4.5kw inverter lasted 1 1/2hrs, waste of £650.
My Transwave 5.5kw rotary convertor really struggles and when eventually motor is running, its too easy to get it to slow down with minimal loading.
I even had one 1 1/2hp 240V motor blowing a 13A fuse 1 in 3 startups.
Whichever way you are going, its going to need a large startup far higher than me and i struggle.
Initial movement of the piston creates pressure, when tanks empty its easy to startup. The current draw can be higher than 16A on a 240V single ph 2.25kw cap start.
Likewise on another machine my 2.25kw 3ph 400V needs at least 7.5kw just on low gearing, no way can i approach normal speeds from stationary and thats best part of £1100. My 4.5kw inverter lasted 1 1/2hrs, waste of £650.
My Transwave 5.5kw rotary convertor really struggles and when eventually motor is running, its too easy to get it to slow down with minimal loading.
I even had one 1 1/2hp 240V motor blowing a 13A fuse 1 in 3 startups.
Whichever way you are going, its going to need a large startup far higher than me and i struggle.
graffian
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I run a 5hp ingersol rand from a rotary converter. It runs fine. The converter is tuned for a lighter load, so the generated phase drops below 400V. I keep meaning to add a control, to switch the converter on and off and add extra tuning capacitance in, but it's been working fine for 10 years so I just leave it alone. It runs much better with a 5hp 3ph motor than it did with a 5hp 1ph motor.
I tried a static converter with a 3hp ingersol rand, it didn't like starting it
and once the pressure got to something like 50psi it sucked the boost back in on every compression. I wired my 5hp motor in as an idler and it worked well enough to spray my GSX, it still had starting issues.
I would have thought you would need to underate a VFD[inverter].
If I didn't have all the other 3phase stuff I would get several single
phase compressors. That's probably your best bet.
I tried a static converter with a 3hp ingersol rand, it didn't like starting it
and once the pressure got to something like 50psi it sucked the boost back in on every compression. I wired my 5hp motor in as an idler and it worked well enough to spray my GSX, it still had starting issues.
I would have thought you would need to underate a VFD[inverter].
If I didn't have all the other 3phase stuff I would get several single
phase compressors. That's probably your best bet.
rtbcomp
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You've got a problem if it trips the RCD!
Sounds like you may have the wrong type of unloading valve fitted. There are two types instant and delayed.
Most compressors use the delayed type which doesn't close until pressure in the delivery pipe reaches about 20 psi, upto that point most of the air from the pump is expelled to atmosphere. This gives the motor an easy start.
Those fitted with an instant type usually have a separate delayed action valve.
Tricky
Its a bloody mine field Ill rind drives direct to see if they will guarantee there units working.
Its a bloody mine field Ill rind drives direct to see if they will guarantee there units working.
ajlelectronics
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Is it feasible to get your mains supply upgraded to 3 phase? I have it in my workshop and wouldn't be without it. I daresay it will be pricy to install it though.
No they wont, collared me for a 5kw plug and play inverter which didnt do the job, input stage packed up after 1 1/2hrs. Repair bill well in excess of £240 on top of £550 for that inverter plus £1100 for latest 7.5kw which is still going. Reminds me must get dosh off them after 18 months or get it back.
Theyre pretty good in certain areas.
RT my every day compressors a cheap Machine Mart Boxer 3hp driving separate pump, looks like now discontinued 12 yrs on.
It will trip the rcd type B when either shut off whilst motor running and or certain times when its peaking the pressure back up.
Inverter fed from an rcd 32A type C will throw the RCCD 80Milli amp feeding the rcd's under serious load. Fuse to premises wire tagged is only 65A was 85A.
rtbcomp
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I think you mean MCB
