Powering a 120VAC LED lamp on my Nichols toolroom mill (240VAC, 1 phase)

So I ended up a while back with a Nichols tool room horizontal mill at the agreeable "get it out of here" price. It had been converted to a non-geared 3 Hp 3 phase motor with a single drive pulley. Getting tired on one speed, I purchased a nice 3 Hp Pacific Scientific industrial 180VDC permanent magnet motor. I am in the process of removing the original motor control, drum direction switches and power switch to convert to a KB DC motor controller.

I would like to mount a spare Moffatt task lamp with a PR30 led reflector bulb (7 watts at 120VAC).

I have two possible ways of powering it.

1) add a long 120VAC cord and fine an unused outlet somewhere.

2) Add a small 240V to 120V step down transformer to power the LED bulb. I am packaging the drive electronics anyway so there is some space to add a fuse and transformer.

I am tempted to use option 2 as it will be the cleanest wiring. Any thoughts on how many VA I would need for a 7W 120VAC led bulb? I know know the obvious answer is slightly more than 7VA, but I have been burned in the past by step up/down transformers and odd load currents causing overheating issues.

Thanks

Option 2 is fine.

I doubt you will see many 240:120 transformers below about 100VA, and 20VA should be plenty. There's little wrong with going too large so that would be my approach.

Another option is to get a 240V or 120-277V bulb, which can be powered directly off the 240V input.

Option 1:

I installed a Weidmuller GFI outlet that has a din rail mount on the back for my led tube lamp rated at 100-240vac.
Could have easily used 240vac from the machine power source but wanted a light on without the machine turned on.
Reason is that I use the light for inspecting parts chucked in the machine. No regrets.

Weidmuller 794000 0037 GFI Outlet 125v 15a NEW | eBay

(only using ebay for the picture)

If you wanted to go cheap, couldn't you use a travel transformer for a 7W load?

SINGWAY AC 110-120V to 220-240V Step Up&Down Dual Voltage Converter Transformer | eBay

PS: Can't you tap 120V off of a 240V line?

crrmeyer said:

So I ended up a while back with a Nichols tool room horizontal mill at the agreeable "get it out of here" price. It had been converted to a non-geared 3 Hp 3 phase motor with a single drive pulley. Getting tired on one speed, I purchased a nice 3 Hp Pacific Scientific industrial 180VDC permanent magnet motor. I am in the process of removing the original motor control, drum direction switches and power switch to convert to a KB DC motor controller.

I would like to mount a spare Moffatt task lamp with a PR30 led reflector bulb (7 watts at 120VAC).

I have two possible ways of powering it.

1) add a long 120VAC cord and fine an unused outlet somewhere.

2) Add a small 240V to 120V step down transformer to power the LED bulb. I am packaging the drive electronics anyway so there is some space to add a fuse and transformer.

I am tempted to use option 2 as it will be the cleanest wiring. Any thoughts on how many VA I would need for a 7W 120VAC led bulb? I know know the obvious answer is slightly more than 7VA, but I have been burned in the past by step up/down transformers and odd load currents causing overheating issues.

Thanks

Click to expand...

I "borrowed" a desklamp - literally OFF my desk - for the Alzmetall drillpress and liked the long linear light source and "gooseneck" flexible positioning without rods and hinges so well I'm looking to do something more permanent, same theme, but with two of them to really control shadows and such, any type of workpiece shape or size, then same-again for the mill and lathes:

Realspace LED Gooseneck Lamp 22 12 H Black - Office Depot

This one came with a typical "wall wart" for 120 VAC - which I have at the machines, given "Wye" 3-Phase.

Longer term I want all my machine lights to be 12 VDC LED's - VERY wide choice out of the auto/truck/marine/RV/camper/portable handyman worker-bee market.

Most are weatherproofed and/or/also shock protected so inherently coolant-resistant and easily wiped-clean.

That way, cometh a power-outage, I won't trip over meself in a windowless shop!

For now, I've got magnetic handhelds - "AA and "AAA" powered - stashed in easy grab range here and there. All over the house, actually. Cheap enuf' and wont start a fire like candles can do!

LED's are NOT something as justifies Big Bucks or over-engineering when even batteries-only last as long as they do and the core LED component is only a low-Voltage Diode to begin with.

I jokingly call them EXTINCTION cords for a reason. Just ask Darwin he has given many awards to folks who use them.

doug8cat said:

I jokingly call them EXTINCTION cords for a reason. Just ask Darwin he has given many awards to folks who use them.

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Dad and I had just finished ripping-out my 1940's home's service-entrance and cutting-in a new Square-D "QO", when the retired postman next door came over, asked if we had any advice for his nearly identical home.

Showed us how he'd been running a big chest freezer. Undersized extension cord clear across the room right off the integral garage, held in place against tripping pulling it outta the socket by a stack of carboard boxes full of old papers, books, and fabrics.

And it is HOT to the touch where NOT under the cardboard and fuel?

He had proudly "upgraded" to 30 A plug fuse 'coz it kept blowing the 20A.... and yah wouldn't want the MEAT to spoil, wudd yah?

Glances exchanged between Dad and I ....no need of words ...and Dad went to pick up a second Square-D panel & breakers at his discount price.

No charge, neighbor.

What you have there isn't an extension cord any longer.

You have converted it to a "house-burner circuit".

And my house is so close that WHEN, not IF, it fires-up your one, my house would surely burn as well.

Click to expand...

Right about fifty years-on. Both still stand, unharmed.

Cheaper to do it right than f**k with smelly ashes.

rons said:

Option 1:

I installed a Weidmuller GFI outlet that has a din rail mount on the back for my led tube lamp rated at 100-240vac.
Could have easily used 240vac from the machine power source but wanted a light on without the machine turned on.
Reason is that I use the light for inspecting parts chucked in the machine. No regrets.

Weidmuller 794000 0037 GFI Outlet 125v 15a NEW | eBay

(only using ebay for the picture)

Click to expand...

That doesn't get you 120V if you don't already have it. Running 240V through a 120V GFCI isn't legal, but I'm not sure if it will actually go bang. It will if you hold the test button and it fails to trip.

ptsmith said:

If you wanted to go cheap, couldn't you use a travel transformer for a 7W load?

SINGWAY AC 110-120V to 220-240V Step Up&Down Dual Voltage Converter Transformer | eBay

PS: Can't you tap 120V off of a 240V line?

View attachment 287174

Click to expand...

That only works with a neutral present. If it's fed with a NEMA 6-20 plug or similar, there is no neutral. The extra conductor isn't run for most machinery.

A plain old office-grade emergency light might be worth looking at if a sudden power cut is a hazard. Battery powered, kicks in immediately if the power fails.

SomeoneSomewhere said:

That doesn't get you 120V if you don't already have it. Running 240V through a 120V GFCI isn't legal, but I'm not sure if it will actually go bang. It will if you hold the test button and it fails to trip.

Click to expand...

Read post #1 again until you understand what is meant by:

" 1) add a long 120VAC cord and fine an unused outlet somewhere. "

To me that means the outlet is 120vac. Class is over.

rons said:

Read post #1 again until you understand what is meant by:

" 1) add a long 120VAC cord and fine an unused outlet somewhere. "

To me that means the outlet is 120vac. Class is over.

Click to expand...

Ah, I missed the bit about option 1. Given the reference to a 100-240V light, I thought you were suggesting just running 240V through a 120V outlet.

I think this thread is mostly about ways to avoid option 1, and putting the outlet inside the control cabinet doesn't really improve things much.

If the machine is not wired yet, run a neutral in the power drop and the problem is solved.

SomeoneSomewhere said:

Ah, I missed the bit about option 1. Given the reference to a 100-240V light, I thought you were suggesting just running 240V through a 120V outlet.

I think this thread is mostly about ways to avoid option 1, and putting the outlet inside the control cabinet doesn't really improve things much.

Click to expand...

Yabut... LED's (typically only a Volt or so "natively") are not "120 VAC" critters until yah put them into arrays, and then.. select a PSU that matches the needs of the series/paralled-up "array" on the output and common national grid mains on the input.

Easiest for the OP is to simply select a different light.

One that utilizes whatever power is already handy in any given machine.

Much of the world HAS NO lower wall-outlet Voltage than leg-to-leg of either Delta or Wye 3-P power @ 2XX VAC.

So there isn't even CLOSE to any "shortage" of choices of goods that "JFW", no more special PSU than whatever "wall wart" is already in the box.

Why, then am I adding 12 VDC goods?

Well .... it's a shop. Metals are handled. Machinery motates. Sharp edges live and work there. Some get flung about. Oils and emulsion coolants get sprayed here and there. RUDE s**t in general can happen.

Worklights aren't much use hidden away nor armoured-up. They need to go in harm's way where the work is going-on if they are to "shed some light" onto it.

I'd like any accidentally cut cords or badly smashed-up fixtures to not be ABLE to present a shock hazard, worst-case.

And the auto/truck/marine/RV mass-production market gives more choices of already-sealed and rugged goods and at same or lesser cost than "office" goods.

Most office goods are neither sealed NOR rugged, and many of them are designs that will become hard to clean - traps that gather dirt and swarf.

"Bespoke" machine-tool lighting?

About as badly overpriced as breakfast cereal at nearly four bucks the box for 30 cents worth of whole grain, sugar, and fancy-printed recycled paper.

How hard a choice was that?

Much of the world HAS NO lower wall-outlet Voltage than leg-to-leg of either Delta or Wye 3-P power @ 2XX VAC.

Click to expand...

Most of the world, that's L-N at 230V. L-L is higher again.

But yeah, ELV is the way to go if at all possible. 100-277V input 12V or 24V output power supplies are readily available. Chuck one in the control box.

Something like this: https://www.automationdirect.com/ad...vdc,_12vdc,_48vdc,_din_rail_mount/psb12-030-p

Option 3: Buy another gooseneck light, identical to the first. Mount them both on the machine. Wire them in series... done!

DaveKamp said:

Option 3: Buy another gooseneck light, identical to the first. Mount them both on the machine. Wire them in series... done!

Click to expand...

Dunno. Most of these are "wall wart" class minimalist PSU, even if resident at the lamp head, are built uber-low-dollar austere, and some, if not most, are "switchers"..or think they are?

May have been mentioned before, but get out your magnifying glass and read the fine print on the lamp's power supply. It may have a wide range of allowable input voltage -- up to and including your 240 single phase. If so, get the proper connector (air-conditioner type?) and use it with a fabricated (or purchased) adapter.

Case in point: family Galapagos vacation, on a 100' diesel three-mast sailer (Alta II, I believe.) Young kid with new Sony game hand-held. Retires for the evening, and plugs it into the wall about the same time I read the little sign on the outlet. Whoops, standard US-style wall outlets are wired with 240. Fortunately, power supply was auto-switching, and accepting of that input voltage. International tragedy averted. Plus, there was enough to see and do that the game got almost no use on that trip...

Thanks everyone for the great input. A few details in retrospect I should have been clearer on. The L6-30 receptacle (240VAC, 1 phase, 30A) for the Nichols mill sadly does not have neutral wired to it. I could change outlets and wire up a neutral wire, but would rather solve it an easier way.

With that availability of switcher power supplies with wide allowable input voltages, a low voltage goose neck lamp would be a good option. I thought about that, but decided I liked the look of the Moffatt lights and I had a spare one anyway. Nichols had a lighting option in the catalog that looks a little similar.

Digikey had nice 30VA step down transformers for not much. With a fuse and fuse holder the total cost was less than $20. I had a nice spot in the metal speed control box to mount everything, so it did not require an additional enclosure. I decided to go this lower tech approach and ordered the parts.

In retrospect, I probably should have used a low voltage switcher power supply connected to the Moffatt lamp retrofitted with a low voltage LED in the switched light bulb socket.

One public service announcement if you have more time than money for your projects:
If you mail a check or money order with your order to Digikey (great electronics parts supplier), the have no minimums and shipping is free. They do get to chose the carrier. But for smaller stuff it is often USPS Priority Mail. I usually just add everything to the online order form so I get a good total. It also will then include any tarifs.

crrmeyer said:

One public service announcement if you have more time than money for your projects:
If you mail a check or money order with your order to Digikey (great electronics parts supplier), the have no minimums and shipping is free.

Click to expand...

LOL! Guy who founded the company published a "DIY" article in the "usual suspects" among Ham rags of choice "back in the day". Then went into kit parts, then "interesting stuff" in general, only a few cheap-paper pages of it at first.

I MAY have "treasure" I bought from him year one or year two still here as never DID make it to the dreamed-for completed project!

He had not done that "publication" so "the Old Guard" ("THREE letter call" hams) got to know he was a real person, his company might have failed back when it was "dead tree" tiny adverts, later newsprint flyers in the mail full of all manner of salvage and remaindered "stuff".

Look at the name of the city.

Some of us wudda classed it a sure-fire scam!

Thanks again for all your input. Here is the follow up.

One worry I had on this was having too small of a transformer and ending up with over heating due to less than perfectly sinusoidal load currents. So I used a 30VA step-down transformer for the 7VA load. Unfortunately the the transformer was insufficiently loaded and the 7 VA LED was running at 140 VAC instead of 120VAC. The current was also running 19% high. I did wire the transformer to a Variac to confirm when the input voltage was adjusted so the transformer output was 120 VAC, the LED current was as expected. When the Variac voltage was increased to 120VAC, the LED brightness also increased. Not a constant current design.

The possible solutions I saw were:

1) Just use the 120 VAC LED bulb

2) Order a smaller rated transformer, such as 12VA. This should result in a higher transformer load percentage and lower output voltage. If I did this, I would confirm output voltage with the transformer manufacturer since their online documentation leaves much to be desired.

3) Add 15W load resistor in parallel to the LED bulb to load the transformer output, thus reducing the voltage.

4) Use a 20W screw-in halogen spotlight bulb (Bulbrite XP BAB/E26 120V 20W Halogen floodlight). With the 20W halogen bulb, the transformer voltage drops to 125VAC. This bulb is rated at typically 2000 hour life at 120VAC. Halogen bulbs have a bulb life inversely proportional to the voltage to the 12th power from previous illuminators I have worked on. So at 125VAC, the life would drop to 1200 hours.

Currently I am using option 4 as that machine only gets used a couple of hours a month. The 140 lumen brightness at a 38 deg beam angle does have just enough illumination on the part.

Does anyone have any thoughts on generic 120VAC LED bulbs at 140VAC?

Thanks

Many transformers have multiple taps to handle these kinds of supply variations. This could be an option.

If it's a cheap bulb, you're always there when it's running, and the machine disconnect switches the bulb off, I wouldn't worry.