3 phase

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3 phase

This topic has 29 replies, 18 voices, and was last updated 22 October 2018 at 11:33 by Anonymous.

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21 October 2018 at 14:00 #376959
Johnboy25
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@johnboy25
‘Horses for courses’. If I manage to move to a more rural location and there’s three phase on the property I’ll use it for the workshop but until then I happy using VFD inverters with single phase for my needs. I’m not a fan of rotary or static converters. I find the options available with VFD’s such as soft start, deceleration and dc braking for emergency stop function for example most useful. Another advantage is that youn can run the motors at 60Hz (as with my American surface grinder) to get the extra 20% increase in speed. Having said this I’ve being using inverter for increasing power efficiency as well as speed control on industrial equipment since the 80’s on three phase supplies as standard. At the end of the day it’s what your familiar and most comfortable with. 🤔👍

John
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21 October 2018 at 17:06 #376987
Max Tolerance
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@maxtolerance69251
I had three phase fitted many years ago by the then Norweb local supplier. It is a long story but I was fortunate to have it done for free. One problem that I have found is that since the de-nationalisation of the supply industry it can be quite difficult to find a supplier who will support a three phase supply to a domestic property. Most of them now require meter readings via a website or app. However they only have a system for a single reading on the afore mentioned sites.

This leads to difficulties especially when contacting them over the phone. When you mention three meters they think your property is divided up into flats or that you have an ordinary meter, an off-peak meter, and can't count properly. Other problems can arise if one meter has a lower reading than the other ( normal on a mixed three phase / single phase supply) they then think you are doing something dodgy. It means for me that I am tied to one company who do seem to be able to cope. It also helps that I can work quite happily on three phase and fit my own wiring etc.

I have never had a problem running the domestic system alongside my three phase. Everything was done to sixteenth edition regs. originally and seventeenth edition later (not much difference in three phase) The main advantage of the three phase is the loading on a higher voltage is less than by using a VFC on a lower one. And it does depend on the number and types of machines you want to run. Some of my machines especially the specialist swiss types would be extremely difficult to convert or run on a VFC because of the integral multi pole motors used. Although I have fitted a three phase 415v Input inverter onto one of them for the speed control.
21 October 2018 at 18:57 #377000
Anonymous
Three meters? I've only got one meter. My meter is 3-phase; one phase goes off to run the domestic consumer unit after the meter. So I only have one reading. Mind you I did have someone refuse to read the meter. The garage is quite crowded and he took a wrong turn. Having been corrected he muttered about only getting 50p per meter read and stormed out to go next door. Where, much to their amusement, he ranted about the idiot next door with machine tools and it shouldn't be allowed and the government should do something about it.

Andrew
21 October 2018 at 19:05 #377002
Robert Atkinson 2
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@robertatkinson2
A number of people have commented on the inability to use VFC/VSD on equipment with control gear or multiple motors. While it is true that there are difficulties using the variable speed capabilities due to the associated variation in voltage, there is no reason why a converter / drive cannot be left set on 50Hz 100% voltage to provide a 3 phase supply for such machines. You loose the advantage of variable speed but at least get the unit working. Some converters may need a small fixed load for stability but this could be 3 small lights or heater elements.

Robert G8RPI
22 October 2018 at 11:33 #377055
Anonymous
Posted by Robert Atkinson 2 on 21/10/2018 19:05:51:

A number of people have commented on the inability to use VFC/VSD on equipment with control gear or multiple motors. While it is true that there are difficulties using the variable speed capabilities due to the associated variation in voltage, there is no reason why a converter / drive cannot be left set on 50Hz 100% voltage to provide a 3 phase supply for such machines.

Quite so, but it still wouldn't allow me to use the full facilities of my machine tools without significant additions or changes.

Andrew
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