Dual phase upgrade to 3 phase

[WiltsFarmer]

Hi, we are converting old farm buildings to commercial units, and as my father used to run a vacuum pump and compressor in his dairy I always assumed we were on 3 phase. However, having had an electrician check our supply, it turns out we have a dual phase supply with 100A fuses on each. Have already enquired with the local DNO about upgrading and they have stated that the local network will need an upgrade so cost for a pole based line upgrade over about 300 metres is 50-60k. As we are not sure if more than one prospective tenant will need 3 phase we are reluctant to go ahead with the upgrade at this time, so are looking at possibly getting a VFD. The DNO advised our current supply will have a max availability of 46Kva. The prospective tenant is a kitchen manufacturer who uses table saws, CNC router, industrial extractor and a roller door. Could anyone please advise what type of kit we could get to provide a robust upgrade for this unit?
Thanks.

 

[Mike Johnson]

You could find that one of the domestic premises is on the other phase, very unusual to have only two phase supply to anything on a site, check the house before committing to anything.

 

[SparkySy]

Two phase is still around there are a fair few farms on it round my way!
To the OP, if the company that want to use The supply for machines you need to know the total load requirements to know how big the supply will have to be.
Using VFD's would need to be individually sized and fitted to each machine that requires 3 phase, the machine may also need further modification to run from a VFD.
It sounds like it may be mainly 3phase machines so you might have to upgrade, or get an onsite generator for their needs.

 

[brianmoooore]

Motor-generator would be a practical solution.
A few places around here managed to get 'free' 3 phase upgrades by allowing a wind generating company to install a wind turbine n their land, before the government put a stop to on shore turbines.

 

[WiltsFarmer]

You could find that one of the domestic premises is on the other phase, very unusual to have only two phase supply to anything on a site, check the house before committing to anything.

Thanks for your reply. There is no house on our supply now as the farmhouse was sold off many years ago. It was just a supply for running a milking parlour and refrigeration units for bulk milk tanks.

 

[WiltsFarmer]

Two phase is still around there are a fair few farms on it round my way!
To the OP, if the company that want to use The supply for machines you need to know the total load requirements to know how big the supply will have to be.
Using VFD's would need to be individually sized and fitted to each machine that requires 3 phase, the machine may also need further modification to run from a VFD.
It sounds like it may be mainly 3phase machines so you might have to upgrade, or get an onsite generator for their needs.

Thanks for your reply. Yes I am waiting to hear back from the company about the actual power ratings of their kit to try to work out what they will need. I didn't know that their kit would need to be modified to run from VFD's so maybe not the way to go in that case. Do you happen to know if there are any low noise generators on the market?

 

[WiltsFarmer]

Motor-generator would be a practical solution.
A few places around here managed to get 'free' 3 phase upgrades by allowing a wind generating company to install a wind turbine n their land, before the government put a stop to on shore turbines.

Thanks for your reply. If I was to propose a solar company to use a barn roof for an installation, do you think they would think it worthwhile given the situation?

 

[SparkySy]

@WiltsFarmer
Generator wise again it's going to come down to size, none are particularly quiet, I have a friend who runs a fair size Hyundai 3phase set next to his unit and that's not too noisy. And a very nice bit of kit. He has similar situation to yours, only single phase available.
With regard to the solar, it's going to very much depend on the usable roof space available. If there is enough room to make it profitable then they may be interested.
Sy

 

[brianmoooore]

Thanks for your reply. If I was to propose a solar company to use a barn roof for an installation, do you think they would think it worthwhile given the situation?

I can't think of any of my customers who have had a new or reinforced supply fitted for solar, but it might be worthwhile making enquiries.
I do have a customer who was helped to convert a couple of derelict barns, half a mile from anywhere, into a pair of large holiday cottages by virtue of a phone company installing a transmitter 25m from the site, for which they had installed about third of a mile of 11kV overhead lines and a transformer big enough to serve the lot.

 

[pc1966]

Do you happen to know if there are any low noise generators on the market?

Most of the bigger stand-alone units are not too bad for noise, and you do get ones with additional silencing for use at events, etc, where the noise is a big factor.

However, generators have running costs beyond the fuel for them as typically the engine needs servicing initially at something like 50 hours, then in the 200-500 hour sort of interval. We have a 16kVA unit and that (like others to 60-ish kVA typically) is 200 hours which is only about 8 days of continuous running.

The majority of that servicing is just an oil & filter change so £50-100 of stuff and an hour or so time (with a bit of cooling down so you don't scald yourself on hot oil) and actually generators are a damn sight easier to service than most modern cars! But someone has to do it and there is a cost for that somehow.

 

[pc1966]

Just to add that I was lending a hand to our landlord's sparky recently and he mentioned a few of the farms/related places he deals with have been running generator as cheaper than grid electric. Bonkers I know, but these are strange times

 

[nicebutdim]

Just to add that I was lending a hand to our landlord's sparky recently and he mentioned a few of the farms/related places he deals with have been running generator as cheaper than grid electric. Bonkers I know, but these are strange times

Provided the power is generated for agricultural purposes, they can still (legally) use rebated (red) diesel, otherwise I don't imagine they'd make any saving.

 

[pc1966]

Provided the power is generated for agricultural purposes, they can still (legally) use rebated (red) diesel, otherwise I don't imagine they'd make any saving.

In these cases that would be true.

More generally I don't know as I don't think many folks make use of co-generation (using waste heat for warming the place). Typically electricity is about 40% of the fuel, and waste heat the rest, but if you can recover a lot of that for powering radiators, dryers, etc, then you can get close to 80% overall and that is obviously a BIG improvement.

 

[nicebutdim]

A large site I work on will regularly make use of large generator sets, but due to the cost of diesel (the regular stuff), they're generally quite keen on site supplies being up and running ASAP.