PM 3520B question

[Mark Detrick]

I took advantage of the recent Powermatic sale and purchased a 3520B. It arrived yesterday and within an hour or so, and with the help of a friend, it's down in my workshop and running like a charm. There is one thing that I'm not sure about, and although it's probably been asked here previously, my search didn't turn up any results.

When I finished using the lathe I turned the speed dial to 0 and turned the lathe off with the power switch. I was surprised to see that with the power switch off, the RPM indicator is still on and displaying 0 RPMs. Is it normal that the RPM indicator stays ON when the power switch is OFF?

Mark

[Thom Sturgill]

Yes, It's normal. The red button is a motor stop rather than shutting down power in. Many users unplug when done for the day.

[John Sanders]

While I do not own a 3520, my drill press does the same thing. I suspect that the sensor circuitry for the speed display will register weather power to the motor is on or off but rather if it is plugged in. Rotate the head by hand and see if you can get the display to register.

[art pfenn]

I called Powermatic asking about the size of the circuit and they advised to always unplug the machine. It seems that a power surge could fry the inverter. Instead of unplugging it I installed a 220 volt switch. Tomorrow mine arrives!

[Mark Detrick]

Yeah, sounds like unplugging is a good idea. I may install an inline 220V switch and attach it to the lathe rather than unplugging it.
Good luck with your lathe. Be sure to have a friend handy!

[Doug W Swanson]

When I bought my 3520B a few weeks ago, I did some research and found out about the power surge problem. To solve that, I installed a 220V switch just ahead of the receptacle. Works like a charm.

[Ken Fitzgerald]

When you first plug it in, if you turn it on immediately it won't start. That is normal as capacitors in the inverter circuit are charging, I suspect. 2 or 3 seconds after plugging it in, the PM3520B will start immediately.

Some people will throw rocks at my next statement. I don' t care. It's my shop.

I unplug my PM3520B whenever I leave for the day and I unplug all of my equipment if I am leaving for an extended period of time. I just returned from a 3 1/2 week trip to Illinois. Before leaving on the trip, I unplugged everything in my shop and I flipped the 220 breaker for my DC. It leaves less chance for damage in the event of a nearby lightning strike.

I have 1st hand experience repairing GCA air traffic control radar equipment that had a nearby lightning strike run in on the electrical supply lines.

[Dan Forman]

On mine, I sometimes have to turn the red button off, then on again to get it to work after plugging it in. So if it ever fails to start up, try that.

Dan

[mark ravensdale]

This was a good question, which I had no idea abt, my Jet 3520b arrives next Tuesday (powermatic but in Europe) and I will be sure to either unplug it or switch off at the socket when I have done making shavins with it (can't wait!!!)

[David DeCristoforo]

One of the great joys of modern electronics. They are never actually "turned off". Like your TV which is always on even when it's off. So, in addition to the risk of the electronics getting fried by a power surge of some kind, the device is always using power to keep the little LEDs glowing. With some devices, it is not a problem to have them on a switched circuit that can be turned off to totally cut power to the device. But if the device in question has any "memory" for the settings or programing, this can be erased by cutting the power so that you have to go through the whole setup process every time you want to use it.

[mark ravensdale]

That's right David, I remember when VHS video recorders first arrived in the Uk if you unplugged them by accident then you had to start reprogramming the correct time and what not into them again (now you know how I lost my hair ;-)
but these days most devices seem to have battery backup of some kind (usually lithium now???) and these batteries can last for many years (hopefully!!!)
does the 3520b have battery backup for the settings in the inverter???
or would leaving it unplugged for a length of time risk loosing any factory programmed settings??? (I'am no expert on these matters so would be interested in knowing)

[Jon Nuckles]

I always unplug mine when I finish with it for the day. On rare occasions, I get caught up in flat work and don't plug it in for a couple of weeks. Never a problem when I return to it.

[Faust M. Ruggiero]

I plug into a 220 volt switched receptacle but I somehow never reach back and shut it off. I've been lucky so far but I would be better off shutting it down. I don't know about your house but with all the tiny glowing LED's that are part of the new devices, my house glows in the dark. Heck, the thermostats alone can light the hallway and the charging lights on the oven, coffee maker and phone are enough to illuminate the kitchen. It's hard to make a room dark any more.
faust

[Mark Detrick]

I know what you mean. My office looks like a spaceship in the dark!

[robert baccus]

The red button switch disconect is a safety. In case you lose power with the lathe on it will not come back on unexpectedly when the power returns. Quite a few bigger machines have this---good.

[Ken Glass]

Ken,
I do the same as you....one question: Why would you ever leave Idaho for Illinois unless it was to visit relatives? LOL

[Ken Fitzgerald]

Ken,
I do the same as you....one question: Why would you ever leave Idaho for Illinois unless it was to visit relatives? LOL

Well......last year my oldest son and I attended the NASCAR races one weekend in Bristol, TN. That is one reason....but mainly just to visit relatives and friends......Ken! LOL!

[Anthony Cayll]

I asked Powermatic about that and they said not to leave it plugged in. I unplug mine every day.

[Ken Barney]

Living in Central Florida (the lightning capital of the United States) I always unplug my 3520B when I'm done. Note that I wrote 'unplug,' not 'switch off.' A switch is no match for a nearby lightning strike.

In 2008 lightning struck the 85 foot tall Sycamore tree that was 10 feet from my driveway. It traveled down trunk and arced from the tree to the driver side door of my truck, literally blowing a half dollar-sized in the door, blew the mirror off the door, and completely fried all of the electronics. $14,000 of damage once repaired. But wait..., it gets better. The lightning arced from my truck to my wife's car parked next to it, taking out the main computer in it.

Not done yet....,

Still not finding the ground it was looking for, it jumped from the wife's car to the house some 30-35 feet away. It finally found the earth ground in the electrical service panel on the opposite side of my house. But along the way it blew the tranformer for the low voltage outdoor lights completely off the house, took out 2 computers, 1 printer, 3 televisions, a microwave oven, the cordless phone, and the sprinkler control system.

The saddest part of this tale of woe is that all of this happened before I started turning (see "85 foot tall Sycamore tree" from above). Living in a subdivision, they had to bring in a crane to safely take it down which brought the tree removal fee to just over $2,800.

So yeah, I always UNPLUG my lathe when I'm done for the day and never turn when there's a Central Florida thunderstorm.

[Mark Detrick]

Point well taken :)

[mark ravensdale]

Wow!!!
i used to be into ham radio in a big way, and a good friend of mine had a strike to one of his antennas, it totally wrecked the wiring in the house and destroyed every electrical item that was plugged in (including his radios which where worth many many thousands of UK pounds) he showed me the fibre-glass antenna that had been struck and it looked like someone had packed half pound of c4 in it and detonated it,
you just don't mess with old mother nature!!!

[Jamie Donaldson]

Ken, if it will make you feel any better, a lightning struck tree is seldom any good for turning. The heat from the strike fries the sap and causes ring shakes in most cases.