Inverter / Variable Frequency drive unit

[Steve_S]

Hi Guys

Have the collected wisdom got any thoughts on Inverter / Variable Frequency drive unit ? are they any good ? the more you pay will they be better ?

Have been looking on Fleabay and found these ones

http://www.ebay.co.uk/itm/VARIABLE-FREQ ... 3cae6eafad

very cheap compared to other makes most likely having cheap components in them. But they will mostly all come out of china what ever the cost

Or would this be a better bet?

http://www.ebay.co.uk/itm/IMO-Jaguar-0- ... 2742&rt=nc

After faffing around with 240v motors not having any joy will get a 3 phase motor of around 1hp i think should be ok (tho original motor I cant get at all winding ends to use it. Its star and the join is buried in the windings ) and run an Inverter / Variable Frequency drive unit


Thanks

Steve

[LesT]

Hi Steve,

I have a couple of these things running machines.
One of them is from these people:
http://www.ebay.co.uk/itm/1-HP-240V-1-P ... 58b80bc2be
Like anything else I suppose, if you want a really good one it isn't going to be cheap. If on the other hand its only for occasional hobby use then cheap might be just fine.(Like your 72 quid one)
A big difference between cheap and dear is the quality of the enclosure (i.e. IP Rating). A cheap one will need to be protected from dust and dirt otherwise it may not last long.
Have a look on Youtube for videos about VFDs, also I saw a rather good video showing an Invertor here:
https://www.youtube.com/watch?v=lTCmd3fJ0iE

Les.T.

[dazz]

Hello

Here is my effort : https://www.youtube.com/watch?v=KJG5ohpvsVU

The Chinese have a saying that the quality is remembered long after the price is forgotten.
If you intend to do a decent job of installation you might as well get a decent VFD and motor.

[rpwilson]

Mines got a Jaguar Cub inverter, at least 20 years old according to the guys at Jaguar, so it looks like Jaguar make reliable inverters. It doesn't have speed control, so I'm seriously considering upgrading to a modern one, so I can get bottom speed down from 70, and yes, I'd have a Jaguar Cub again.

Do all inverters have fans in them? My present one doesn't, and I thought the one in the video was quite noisy, though I suppose when the lathe itself is running, you don't hear it.

[dazz]

Hello
The whining noise you can hear is the fan mounted on the back of the motor. It's not that loud. The auto gain control on the camera sound makes it sound louder than it really is.

Inverter technology has come a long way in the last 20 years.

[rpwilson]

Hello
The whining noise you can hear is the fan mounted on the back of the motor. It's not that loud. The auto gain control on the camera sound makes it sound louder than it really is.

Inverter technology has come a long way in the last 20 years.

Is the fan to help cool the motor at low speed? What did you use for it?

While you are on, a week or so ago I sent a PM about the taper turning/copy device, did you get it?

[dazz]

Hello

I used a recycled centrifugal fan.
The fan cools the motor at all speeds.
Fitting a separate fan motor ensures cooling at low speeds and during periods when the motor has stopped.
At high speeds, it avoids power being sucked from the motor driving a fan supplying too much air. Power increases with the square of fan speed.
Double speed = 4x power to drive the fan.

No, no message received.

[rpwilson]

Hello

I used a recycled centrifugal fan.
The fan cools the motor at all speeds.
Fitting a separate fan motor ensures cooling at low speeds and during periods when the motor has stopped.
At high speeds, it avoids power being sucked from the motor driving a fan supplying too much air. Power increases with the square of fan speed.
Double speed = 4x power to drive the fan.

No, no message received.

OK then, I'm building a taper turning/copying attachment for my Denford Synchro, using the Denford drawings as far as possible. I've done the long bar, the blocks, the swivelling plate, and have a pattern at the foundry for the brackets. What I need now are some dimensions for the spring attachment pins, the stylus and the spring housings, because the drawings for these don't seem to have survived. I know you have one, and so any information would be useful. With the aid of the materials list I can probably work it out after a fashion, but the more information the better. I like your 'slipper' follower, and will probably make one of those instead of the ball bearing original. I've made the swivelling plate from 1/4" plate, which is cold drawn, rather than 1/8", becasue all I could get in that thickness was sheared edge.

[LesT]

This probably isn't much use to you, but I found an assembly drawing which shows a bit of the taper turning attachment.
Les.T.

[rpwilson]

Yes, thats the one that is already on this site, but thanks anyway.

Richard