Running a big machine from a domestic supply

[SamI]

Long before VFD's, Reduced Voltage Motor Controllers (RV) were used to address the problems caused by motor inrush currents. They used either tapped inductors or resistors to permit the motor to start and minimize voltage dip and sag that would affect adjacent systems.

Presumably this does a similar thing to programming a VFD for a soft start?

Thank you all for your suggestions. I think for now I'm going to hold out for one of the other machines that could be going in the near future - I think they may be a better match for my needs. Your help is still very much appreciated and there's a lot of useful information that I'll refer back to when I do end up getting a machine!

TheArsonSmith - I'm looking forwards to your video on the wiring and programming (it's probably out now - I should go and check!). There is a lot of conflicting information out there as to the best way of tackling this problem and it is reassuring to see that you have done it successfully!

 

[GordonL]

I have been running my shop on a home made phase converter with relays and capacitors for years. I have never had any problem. In the home shop you are not too likely to use the HP capacity of the big industrial machines. Total investment for me was about $100. The biggest expense is finding a used idler motor. If you look around you can find big old ugly motors cheap. Hide the idler motor in the other room.

Apparently this forum will not let me post a link.

 

[rcaffin]

Have you thought of contacting your supply company and asking for an upgrade to 3-phase? Convince them you are going to need the power. They might prefer to go 3-phase rather than risk burning out one phase in their transformers. Seriously.

I did this, and got 3-phase at 60 A per phase. The biggest expense was probably their guy up the pole, but that was on their side of the connection.

Cheers

 

[SamI]

Have you thought of contacting your supply company and asking for an upgrade to 3-phase? Convince them you are going to need the power. They might prefer to go 3-phase rather than risk burning out one phase in their transformers. Seriously.

I did this, and got 3-phase at 60 A per phase. The biggest expense was probably their guy up the pole, but that was on their side of the connection.

Cheers

I had considered this however I am not planning on being in our current property long term. When we move in (hopefully) the near future then a large workshop and a 3 phase supply are high up on my list of priorities!

 

[warrjon]

I run my 5hp 3ph mill from a VFD as I am limited to 20amps to the house a RPC was not an option. I do not take huge cuts in steel so have never drawn 20amps or I would trip out the load limiter. I have the VFD set to ramp the motor slowly to limit the inrush. My power feeds are 110V single phase so do not run from the VFD.

I would not recommend running motors of different HP and/or RPM off a single VFD as you will need to program the motor parameters into the VFD. If you can make an RPC cheap enough then this may be the way to go.