Single to three phase inverter

[Fazerruss]

Hi all, I'm looking for a bit of guidance on my options. I'm starting to keep my eye out for an inverter to run the bridgeport milling head on my Tom senior.
I've seen for sale the odd transwave static converter on various sites and also VFD inverters of various makes.
The speed control option would be nice but not essential as I can still change the belt over on the pulleys.
Here is a pic of the motor data plate.
It's a half horse power but what does the high and low volts suggest?
Is this the star and delta connection that gives the option of low and high?
Three phase is not my area of expertise but am I right in thinking star wiring gives the higher torque and low speed and delta vise versa?



Thank you

 

[piman]

Hello Fazeruss,

it is a dual voltage motor, with the range of the low and high voltages it will run at. The sticker says its 380 so will need changing to the 208/220 volt setting. This is ideal for a VFR as if it were only 380/440 it would need an expensive single phase to three phase 415 VFR.

Open the terminal box and you should see six terminals, three of which will be connected by straps and three terminals where the phases go, this is the high connection. Remove the straps and connect them across each of the three pairs of terminals and you can now run the motor at 220 volt three phase. Generally there will be a connection diagram inside the terminal box lid.

Alec

 

[rikrobson]

Unless you need a 3 phase supply for your workshop, i.e. to run a number of machines I would just get a VFD. This will run the motor fine and you can "tune" the VFD to the motors characteristics, Frequency,torque etc. As @piman says you'll need to make sure its on the low voltage or Delta setting. (this is one coil between each phase, where star is two) The connection cover usually has the instructions, but they are either 4 or 6 poles. the 4 pole ones have one end of the coils loose and these are put on 3 of the poles. If the coils are W V X then id (W1 V2) (V1 X2) (X1 W2). If its the 6 poles there should be little brass strips. you will need 3 across each pair of poles. In both cases the input phases are connected to the 3 poles. If the motor goes the wrong way just swap 2 of the input phases.

Edit. I just took a better look at your Pic. you'll need the LO volts setting as per the picture on the Data plate

Also if you get a VFD I'd run it at 60Hz as the Max and have speed control, which will lower the frequency and therefore speed if needed

 

[Fazerruss]

What would you recommend for the minimum frequency? And would there be a drop in torque below 50hz?

 

[Fazerruss]

Also any recommendation's for make of VFD and what to Steer clear of?

 

[rikrobson]

I just bought a cheapich chinese one 1.5kW for My Boxford. That was approx £80 on ebay iirc.

It will need setting up initially. there are about 30 parameters depending on how you want to control it.

There ae several options on control. You can use the VFD panel or make your own panel. Also the speed control can by via the panel, a potentiometer or digitally

I set up mine with a fwd/stop/rev switch and an emergency stop with a potentiomer to control the speed. I also added a cheap Tach disply which cam with a hall effect sensor and put a tiny neodinium magnet on the spindle.

I still use the Belts and Backgear to change the speed, but have the fine control to reduce the speed if necesary. You do loose a bit of torque at very low revs.

There are settings for the max frequency of the motor, parameters for the torque curve and speed up and slow down times. There are also alot of other setting like how it will respond on powering up etc, which you won't need to bother with. They needed to make them all things to all men, not just lathe mill operators

 

[Fazerruss]

I just bought a cheapich chinese one 1.5kW for My Boxford. That was approx £80 on ebay iirc.

It will need setting up initially. there are about 30 parameters depending on how you want to control it.

There ae several options on control. You can use the VFD panel or make your own panel. Also the speed control can by via the panel, a potentiometer or digitally

I set up mine with a fwd/stop/rev switch and an emergency stop with a potentiomer to control the speed. I also added a cheap Tach disply which cam with a hall effect sensor and put a tiny neodinium magnet on the spindle.

I still use the Belts and Backgear to change the speed, but have the fine control to reduce the speed if necesary. You do loose a bit of torque at very low revs.

There are settings for the max frequency of the motor, parameters for the torque curve and speed up and slow down times. There are also alot of other setting like how it will respond on powering up etc, which you won't need to bother with. They needed to make them all things to all men, not just lathe mill operators

What make is yours?
I've seen a Delta on the bay not far from me and wonder if they're any good?

 

[daleyd]

There are a couple of Schneider altivar 312 1.5kw ones on eBay at the moment, £85. (I have one of these at home and it's great)

Cracking price for a real decent bit of kit, might be worth a look? (I've no connection to the seller they just showed up on a saved search of mine)

http://m.ebay.co.uk/itm/Schneider-E...%3Abd602ee41590a2a2388b5abdffb57d8e%7Ciid%3A8

 

[ronan]

Fazerruss, any pictures of the bridgeport conversion to your Tom Senior ? I am doing the same thing to mine, with a head i bought off a forum member last year. When upping or downing the hertz you run the motor, consider, if you run the motor too slowly, you risk over heating problems as the fan isn't running as fast, and if you run the motor too quickly, you risk overloading the motor bearings. I paid a bit more for my inverters and bought abb made units. I am sure the chinese ones are ok though.

 

[daleyd]

Fazerruss, any pictures of the bridgeport conversion to your Tom Senior ? I am doing the same thing to mine, with a head i bought off a forum member last year. When upping or downing the hertz you run the motor, consider, if you run the motor too slowly, you risk over heating problems as the fan isn't running as fast, and if you run the motor too quickly, you risk overloading the motor bearings. I paid a bit more for my inverters and bought abb made units. I am sure the chinese ones are ok though.

For milling operations you'd probably be OK, it's easy enough to set up minimum and maximum frequencies in the inverter though. If your running it lower than around 15hz ish for extended periods I'd look at forced cooling( depending on motor and fan, have a feel around when running at low speeds to check you have some airflow. If your paranoid stick a temp sensor/thermistor in the windings. Some drives can even guesstimate the temperature from the motor winding characteristics.)

 

[Fazerruss]

Fazerruss, any pictures of the bridgeport conversion to your Tom Senior ? I am doing the same thing to mine, with a head i bought off a forum member last year. When upping or downing the hertz you run the motor, consider, if you run the motor too slowly, you risk over heating problems as the fan isn't running as fast, and if you run the motor too quickly, you risk overloading the motor bearings. I paid a bit more for my inverters and bought abb made units. I am sure the chinese ones are ok though.

No pictures of the parts for the conversion yet as I still need to make them. I'm currently on with the rebuild after stripping the mill and a respray.
I'm going to make a large plate to bolt to the top and anchor to the over arm support. It will have a steel block which the knuckle on the back of the head will clamp to.
Here is the mill so far....


And the back of the head....


And top. I'm going to utilise the motor fixing holes rather than other designs that clamp to the dovetail slides. This will alow me to tilt the head in 2 axis.



Here is the thread

http://www.mig-welding.co.uk/forum/threads/theres-going-to-be-a-wedding-sort-of.69529/#post-937376

 

[Fazerruss]

There are a couple of Schneider altivar 312 1.5kw ones on eBay at the moment, £85. (I have one of these at home and it's great)

Cracking price for a real decent bit of kit, might be worth a look? (I've no connection to the seller they just showed up on a saved search of mine)

http://m.ebay.co.uk/itm/Schneider-Electric-ATV312HU15M2-ALTIVAR-312-Inverter-Drive-/182427182943?hash=item2a7981e75f:g:~iYAAOSw-0xYgL7N&_trkparms=pageci%3A90a9d581-df47-11e6-96db-74dbd180f74e%7Cparentrq%3Abd602ee41590a2a2388b5abdffb57d8e%7Ciid%3A8

Thanks I'll have a nosey at them.

 

[Fazerruss]

Fazerruss, any pictures of the bridgeport conversion to your Tom Senior ? I am doing the same thing to mine, with a head i bought off a forum member last year. When upping or downing the hertz you run the motor, consider, if you run the motor too slowly, you risk over heating problems as the fan isn't running as fast, and if you run the motor too quickly, you risk overloading the motor bearings. I paid a bit more for my inverters and bought abb made units. I am sure the chinese ones are ok though.

This may be useful to you. I saved it from an eabay listing a while ago. It may be useful depending on how your head attaches.

 

[ronan]

Thanks fazerruss, my machine hasn't the round bar overarm, but an iron casting. Its a pity as the round arm would be easier to do i reckon. My bridgy head is the variable speed type (2j ?).

http://www.anf.nildram.co.uk/workshop/major/major.html

 

[daleyd]

Thanks I'll have a nosey at them.

I confess I do work for Schneider, but I can honestly say they are superb bits of kit. If you have any questions feel free to ask.

There is (free) software to set them up and monitor/faultfind you can make up a comms cable easy enough with an RS232 -485 adaptor (couple of quid off ebay) and a chopped up Ethernet cable. The 312 drives also have the facility to switch between 2 motors so you can use one drive for several applications.

You can get a Chinese generic drive for similar money which in all honesty would probably work perfectly fine, but if these are genuine new altivar 312 drives they are a bargain at that price (£200+ cheapest elsewhere)

 

[Fazerruss]

I confess I do work for Schneider, but I can honestly say they are superb bits of kit. If you have any questions feel free to ask.

There is (free) software to set them up and monitor/faultfind you can make up a comms cable easy enough with an RS232 -485 adaptor (couple of quid off ebay) and a chopped up Ethernet cable. The 312 drives also have the facility to switch between 2 motors so you can use one drive for several applications.

You can get a Chinese generic drive for similar money which in all honesty would probably work perfectly fine, but if these are genuine new altivar 312 drives they are a bargain at that price (£200+ cheapest elsewhere)

My finger is hovering over the buy it now button!
Are they reasonably straightforward to set up?
I like the option of being able to use it on another machine if required (obviously not at the same time)

The seller has good feedback, I'm going to bite the bullet.
You do realise you have now shot yourself in the foot. I'll be pestering you for advice if I can't get it working!

 

[daleyd]

My finger is hovering over the buy it now button!
Are they reasonably straightforward to set up?
I like the option of being able to use it on another machine if required (obviously not at the same time)

The seller has good feedback, I'm going to bite the bullet.
You do realise you have now shot yourself in the foot. I'll be pestering you gor advice if I can get ut working!

Dead easy - they can very complicated if you want them to be but in all honesty you will only need to change a few things to get you going.

The manuals are very good and comprehensive too. The website has them all available for download but I can send them you if you want? If you want to make a cable up let me know I'll let you know what you need and how to connect.

 

[Fazerruss]

I've bought it! Bargain!!

£267+VAT from RS

Thank you for the heads up @daleyd

 

[daleyd]

The cheapest I've seen them is just over £200 at inverterdrives(?), so even compared to that they are a bargain.

Give us a shout if you need any info on setting up etc.