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Post by walter on Nov 20, 2008 21:15:06 GMT
Hi all, newbie alert
Sorry if this has been asked before, but i`ve only just found this site.
I was wondering if anyone had any experience of of the newish digital type inverters (single to 3 phase) that they could pass on to me.
I have an old 3 phase surface planer, i understand i may have to change the existing motor as it may not be suitable for this type of inverter, but was wondering if anyone else had undertaken such a task & what the pitfalls they had encountered.
Thanks.
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Post by jfc on Nov 20, 2008 21:20:34 GMT
Hi Walter and welcome .
No help in info i'm afraid but i do know Scott and Sargent sell second hand aswell as new inverters . The sales team there will be able to help you if no one here can .
Or should that be , welcome to the forum , i'm sorry i cant help but i'm sure someone will be along soon that can ;D
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Post by walter on Nov 20, 2008 22:04:39 GMT
Thanks for the welcome & Scott & Sargent JFC.
I found their web site, but they seem to only have rotary & static inverters which i believe are not very energy efficient, though i may well be wrong.
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Post by jonnyd on Nov 20, 2008 22:10:36 GMT
There is a company near me who make inverters called silverdrive 01775 822400. I looked into getting one and got good advice but moved to a workshop with 3 phase instead. Might be worth a phonecall.
jon
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Post by walter on Nov 20, 2008 22:13:48 GMT
Thanks Jonny D,
Roughly were abouts are they?
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Post by jonnyd on Nov 20, 2008 22:18:48 GMT
They are in a village called Donington which is between Boston and Grantham in Lincolnshire.
jon
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Post by walter on Nov 20, 2008 22:20:47 GMT
Great that`s not that far, Many thanks Jonny
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Post by Keith on Nov 21, 2008 7:36:19 GMT
I looked into this a while ago and found that the rotary inverters are the best bet, easiest to use and most adaptable; most expensove too  . The electronic inverters produce 3 phase 240V not 3 phase 415V which a lot of motors need, it will depend if your motor will work with the lower voltage. If you take a look at www.powercapacitors.co.uk there is a load of info there. |
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Post by 9fingers on Nov 21, 2008 12:44:47 GMT
Walter,
The first step is to look at the rating plate of your motor and see if it say 240/415 volts or similar or just 415volts. also see how many horsepower (or watts/746) your motor needs
As Keith has said MOST inverters can only produce 240 volt 3 phase from a single phase 240 volt input. A few, more expensive ones will do a voltage step up as well to give 415v 3 phase out from 240v single phase in.
Above 3 - 4hp typically, inverters will want 3 phase INPUT so no good for you. This might seem strange but in higher power applications the inverter is being used for its abilitiy to control the speed of the motor and to give it soft start and braking etc. You will get these features as well from the single phase input type as well as what you need ie single to 3 phase conversion.
Inverters must be rated to the full rating of the motor even if you think you will not be 'working it that hard'. Inverters are quite clever now and make measurements of the motor and will shut down if they decide the the motor will overload the inverter.
Below 3hp and 240 3phase motor an inverter is possibly what you need
Above 3hp and 415v 3 phase motor then a static or rotary CONVERTER is the best choice unless you can get 3 phase supply put in.
Efficiency is not a consideration. At these sort of power levels any inefficient process would produce embarassing levels of heat (smoke + flames etc!) all inverters/converters are very efficient. Most of the heat will appear in the motor itself no matter which way you power it.
Motor changing is not often the best route especially with older machines as shaft diameters, motor mounting holes are often different and unless you are a metal worker too, there are a raft of minor mechanical issues to solve. Decent quality new motors are expensive and only available in single phase up to 3-4HP Sometimes they don't have enough starting torque (turning power at low speeds) to start machines with belt drives esp in cold weather.
If you need more help them please PM me with more details of your motor and I'll try and help.
Bob
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Post by walter on Nov 22, 2008 21:18:04 GMT
Thanks for the replies.
Keith,
Power capacitiors look like they will be at Harrogate, so hopefully i`ll be able to find out some more information from them on Friday.
Bob,
Thanks for that information, i`ll see what happens friday & if necessary take you up on your kind offer.
Thanks again, Walter
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. The electronic inverters produce 3 phase 240V not 3 phase 415V which a lot of motors need, it will depend if your motor will work with the lower voltage.