[neurofen]

picture attached...

Ok, so in a frenzy I bought an inverter for my spindle thinking that i'd stick a plug on it. Failing to take into account all sorts of things that i should have done. :/

Anyway. The inverter manufacturer recommends a 24Amp fuse (which is more than a standard 13amp home plug). So i'm going to build the inverter, RFI filter and fuse/fuseholder into a cabinet.

My question is this: Can I safely run a cable from the fuse box, out of the cabinet and straight into a home wall socket, (uk, socket ring, 30Amp).

Also, If i put a plug on the end hardwired without a fuse, is this ok? technically speaking of course, since there is a fuse in the inverter cabinet.


Enter the fire brigade/ laughter from electricians.

[john-100]

I'd look at this industrial 32A plug and socket

32 Amp 3 Pin Plug & Panel Socket Blue 240v Garage Workshop 1 Phase NEXTDAY £3.99 | eBay

if you use a 32A cable to connect the plug and inverter
the 32A circuit breaker in the consumer unit will then protect the cable and the plug and socket

John

[neurofen]

thanks john. I take it i'd replace the wall socket with this panel socket? Do you know of any plug and play systems. I'm trying to get away without taking the plug sockets off the wall.

[Al_The_Man]

What is the HP and FLA of the motor?
The motor draws the current, not the VFD.
Al.

[neurofen]

hey al, it's a Chinese spindle so specs are a bit thin on the ground, but it's the 1.5kw version. 8amp it says, not sure if that's at full load. To be honest i'm a bit bewildered by all the various ratings.

Specs of the set up are in the pic attached below.


edit. trying to work this out logically.. on the inverter side of things, printed on the front is a rating of 17.5A input. Is this a provision for the 200% over current feature?

[Al_The_Man]

I don't see any reason for not being able to run off a ring main socket with that size of motor?
VFD's have a over current limit that automatically shuts down if the motor load is exceeded.
I think I mentioned in another link about the minimum rpm for these spindles.
Al.

[neurofen]

aye, i was going to set the minimum freq to approx. 133Hz, which equates to about 8000rpm. Maybe experiment and drop it to about 100Hz. The chinese spisnlde thread here was good also, but i have to admit im only 65 pages in to it so far.

I'm going to give the VFD distributors a call monday ask them to explain a few things, they are extremely helpful, and even knocked £200 off my VFD as the one i wanted wasn't in stock. I couldn't believe it.

Do you have any idea about the difference in current one side of the vfd to the other. ie if the motor is drawing 8amps at a point in time, how much would be comming out the wall to feed it? I know energy is lost inbetween as heat, but there must be plenty of other factors involved.

[Al_The_Man]

A VFD basically consists of a 3phase rectifier and a DC capacitor bank, which stores energy, which is then switched through to the motor, so there is very little difference between input and output.
The electronics of the VFD does not consume that much.
Al.

[neurofen]

ta, as a temporary measure I managed to hook it up with a fused 13amp plug and some 20amp cable which seems to have done the trick.