Thread: 7.5hp single phase powered lathe

I bought an ex tafe colchester triumph lathe a few years ago and finally got around to setting it up. I dont have 3 phase power so was considering just installing a 3hp single phase motor but in the end decided to go to the extra effort of installing a VFD. I went with a 10hp huanyang 220v VFD which is installed in a fan ventilated cubicle with a window so you can see the VFD display and also a voltage/current display which shows the single phase current going into the VFD. The meter was less than 10 bucks on ebay but is surprisingly good and extremly useful to see how much the machine is loaded. I was initally worried about how much current this was going to draw but based on this meter I can see current is really quite low. Most of the time less than 10 amps on the little stuff I've done so far.. pretty good considering it should theoretically be over 35A at full load.

LCD Digital AC Volt Voltage Amp 2 in 1 Panel Meter Voltmeter Ammeter 5-50A | eBay

From the cubicle 3 phase from the VFD is connected directly to the motor and 240v single phase is supplied seperately to the control transformer which powers the controls and the electromagnetic brake. I got some 8 core dekoron control cable for the controls not really knowing what I was going to do but in the end have only used 2 cores for the run signal to the VFD. This signal comes for the old main motor contactor in the lathe which is now redundant. There is no speed control because the lathe has a centrifugal oil pump so reducing speed would risk stopping the oil supply to the headstock.

Its a clutched machine and I initially had it set up so it would work as you would expect with the motor always running and the clutch engauging to drive the spindle, but the shock load when the clutch engauged was tripping the VFD on overload. I played with all the settings but in the end the only way I could get it to work was to rewire it so the motor starts at the same time the clutch is engauged and then turns off when you disengauge. It takes about 15 seconds for the motor to ramp at start up but in the end I pretty happy with how its been working.

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Nice work, your wiring is very neat, certainly better than my plate of spaghetti...

Did you wire the motor in delta as well? If not you really only have a 4hp ish motor, maybe the reason for the vfd tripping when the clutch is engaged?

I didn't know 240v vfd's got that big.

that is a neat setup

I bought a 3hp huanyung VFD for the Hendey lathe here , I also have a 3 HP new motor . hopefully , the lathe wont be running at full load that often, so as it is , just planning on working at say 50 % of its capacity most of the time, it should be OK But I may have surge current problems like you did on start up.. will see

I wasnt aware of those larger VFD's either , I I thought 3 HP was the biggest you could get in that style . Those Huanyang's all look the same to me . They must have larger switching transistors for the bigger HP models

Mike

Yeah the motors wired delta... but I think spinning up quite a large chuck puts too much load on it suddenly. It did work ok at spindle speeds less than 200 RPM which isnt really much help. I did think about putting a flywheel on the motor but was keen to just get it running.

This size of VFD isnt shown in the manual but I think its just a 20hp 380V unit that is derated to suit the higher current and had the voltage setting changed in the software, was about $450 shipped on ebay. The VSD is rated for 33A output while my 7.5hp motor only needs about 20A full load current in 220V 3 phase. But because its supplied with single phase input will be around 35A max as mentioned so the input rectifier is the bit that limits things. At least I hope this is all right... so far soo good.

You can also buy the measuring device that fits between your 240V outlet wall socket and the power lead itself , it measures watts , current ect.


AU Energy Power Watt Voltage Volt Meter Monitor Analyzer Plug Mini Ammeter 240V | eBay


Might give you a fright when the lathe is under a big load you see the meter spinning around in your house/shed power box ...........$$$$$

Mike

Hi Gallegos

Great looking set up. How many amps on the breakers?

Those power meters look like fun I might pick me up a couple. Does it really not read below 5A?

Hi Mike,
I have one of those but they only go to 15A

Stuart

Its hard wired into the shed board on a 40A breaker.

I never noticed the 5a amp lower limit on the meter... It definitely reads below 5 amps. Though it only happens in this case when unloaded at slow spindle speeds (and even then its still around 4A) or when ramping up or down.

I like the plug in meter that records kwhr.... it would be nice to have something like this built into the incomer to the shed to keep track of how much power i'm using seperately to the main meter.

Originally Posted by gallegos

Its hard wired into the shed board on a 40A breaker.

I never noticed the 5a amp lower limit on the meter... It definitely reads below 5 amps. Though it only happens in this case when unloaded at slow spindle speeds (and even then its still around 4A) or when ramping up or down.

I like the plug in meter that records kwhr.... it would be nice to have something like this built into the incomer to the shed to keep track of how much power i'm using seperately to the main meter.

I reckon my shop costs 75-80 cents an hour if a spindle is running. Just lights cost around 15 cents. My spindles are all around 2.2 kW, my tariff is around 27 cents/kW hr

GQ

Originally Posted by Greg Q

I reckon my shop costs 75-80 cents an hour if a spindle is running. Just lights cost around 15 cents. My spindles are all around 2.2 kW, my tariff is around 27 cents/kW hr

GQ

With the amount of time I'm NOT spending in the shed with my machines I reckon the power companies should be paying me!!

Gallegos- I am also the owner of a Colchester Triumph which I got cheap from H&F (when they sold REAL machines LOL!!!!) but it wasn't in as good condition (cosmetically- it still turns good) as yours. I reckon they pinched the splash guard and they put it on your machine. It's okay, you can keep it I just need to getting around to making one for mine.

Would it be so rude to ask what you paid for it? Mine was just over $2k maybe 8 years ago.

2 grand is pretty good... mine was 4 at auction. Not sure exactly where it came from but there was about 10 triumphs of various ages being sold including one with a longer bed which I missed out on . Its a really nice machine.

Mine is the long bed model.

If I ask nicely would you kindly take a couple of snaps of the splash guard to help me fabricate one?

Not a problem... I'll grab some pics when i get a chance

Thankyou.

pics of the splash guard...
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let me know if you need anything else gerbil.

Thankyou, these pics will come in very handy. I did take some when I was doing a course at the local TAFE, but that was about 3 hard drive crashes ago....