Advice on Clausing drill press

[Joe Gwinn]

Fear mongering maybe, I honestly don't know but maybe this could help someone?

The company is trying to sell their VFD services by intimidating the users of such services. Having a competent industrial electrician is necessary for a place with big motors like those shown.

All the things mentioned can very well happen, but are not at all important when powering a few-horse drill press from a 7.5 horse RPC in a hobby shop. So read the litany, and store the mechanisms in the back of the mind for future reference.

I went through all this circa 2007 when I started buying old machine tools. I didn't have room for a RPC, so that was out, and VFDs it was. If I recall, the mill came with a VFD which I installed, and later added a remote speed control box. I also added a braking resistor. The mill had its original pancake motor (1150 rpm), and still worked fine, and I never added the various filters and inductors recommended for industrial use. The original VFD later failed and was replaced.

With the lathe, I bought a new VFD for that, which also needed a braking resistor so it wouldn't throw a fault code when I stopped the spindle too quickly. For the lathe, I retained the original Fwd-Off-Rev drum switch control, but it now talks only to the VFD.

 

[Joe Gwinn]

Joe, I think I need to use the high voltage option on this but again, I'm not sure. According to Norton America, min amp size is 15A, max is 40A......... American Phase Converters has a video on YouTube, 5 tips on Phase converters I think it was titled, but it said multiply idol motor amps X 1.6, then multiply that number by 1.2.
Now, looking at the sticker on the 7.5 says 200 volts is 22.4A. 22.4 x 1.6= 35.84, multiply that by 1.2 for the 20% security "I don't remember the technical term" and get 43.008, which puts me outside the recommended 40A max.

I watched the video on that. The 20% margin (expressed as a factor of 1.2) isn't all that hard a limit, and being 3 amps over isn't going to matter - the margin is shaved to 18.6%.

The high side amps on the 7.5 idler motor is 19.4, multiply that by the 1.6 = 31.04 x 1.2 = 37.284 amps, barely within the max for the panel.

Nor is that likely to matter because (even though it's close) the drill-press motor is not going to draw anything like that much. Unless you overload it, and then the breaker could well pop, which isn't a problem if it doesn't happen too often.

I'd get the installation manual and read it through. It's not on Amazon; you will need to North American's own website. I'd also check their price and compare with Amazon - sometimes the difference is surprising.

 

[Bill D]

Check the internal braking resister wiring. Many cheap Chinese VFD's have brake terminals that go nowhere. One of my Vfd's is like that. Brake terminals go to blank on the back side of the circuit board. They are not electrically connected to anything. makes you think the resistor is doing something.
Bill D

 

[GregSY]

Most VFDs offer no braking or very limited braking. That's because braking require resistors and VFDs - a tightly packaged product - don't have room for them. Some VFDs, like the one I have, offer the ability to add-on external resistor banks that provide 'real' braking.

But, for most machine tools, it's a wank rather than an actual need. On my lathe, it will slow down all by itself fast enough...and if I want it to slow down faster I use the foot brake which is far more effective and versatile. Imagine that....a modern electronic gizmo that is less useful than a 100 year mechanical gizmo.

People who need VFDs for braking are the people doing things like conveyors or mine shaft lifts or precision automation. Manual machining? Very seldom.

 

[EPAIII]

If you are referring to my post with the quote about 1X speed, please read my post again.

I was not in any way suggesting that any switching be placed between the VFD and the motor. This drill press seems to have a nice, mechanical speed control which can be used with a single setting of the VFD. That is what I was suggesting be used.

Yes, the RPC panel you showed a pic of would be just fine.

As for "I see no reason why a VFD could not be set for 1X speed or 60 Hertz and just left there." The problem is that VFD's...as far as I know....are not meant to be 'deadheaded'. In other words, there should be no swicth between the VFD and the motor. The proper operation is to first power up the VFD, then hit the 'motor start and run' function of the VFD, and it feeds power out to the motor. VFD's are not meant to be 'On' and waiting for someone to flip a switch on their output side to send power they are 'already making' to a motor. A VFD is meant to flow power always, not have it on tap.

 

[BillyA]

I watched the video on that. The 20% margin (expressed as a factor of 1.2) isn't all the hard a limit, and being 3 amps over isn't going to matter - the margin is shaved to 18.6%.


Nor is that likely to matter because (even though it's close) the drill-press motor is not going to draw anything like that much. Unless you overload it, and then the breaker could well pop, which isn't a problem if it doesn't happen too often.

I'd get the installation manual and read it through. It's not oin Amazon; you will need to North American's own website. I'd also chech their price and compare with Amazon - sometimes the difference is surprising.

The North America rpc is actually more expensive on their website for whatever reason???? The listing on ebay as actually THEIR ebay store, but it's a little cheaper on eBay, competition I guess?

 

[Rob F.]

The North America rpc is actually more expensive on their website for whatever reason???? The listing on ebay as actually THEIR ebay store, but it's a little cheaper on eBay, competition I guess?

Be sure to look at shipping costs, I have seen some places put a really high shipping charge to offset a lower sales price. I would be surprised if American rotary did this but be sure to check. Usually companies own web pages are a cheaper price due to not having to pay ebay fees....

 

[BillyA]

Be sure to look at shipping costs, I have seen some places put a really high shipping charge to offset a lower sales price. I would be surprised if American rotary did this but be sure to check. Usually companies own web pages are a cheaper price due to not having to pay ebay fees....

The ebay price of $324 also has free shipping. It's the exact same part number and I don't know what shipping is on there website but no use in finding out in my opinion.

 

[BillyA]

Another thing, I had absolutely no idea that there would be sooooo many options for the receptacles on this plug!!!! In a box here at work, I found ONE!!!!! out of 30 or so that matches the plug on the drill press....... The one part that turns OUT with the narrow blade straight across from it is odd but it's what I need. I haven't found a match online yet but maybe the used one will work, I need the figure out the amp rating for it though.
Everything I see online has the bit on the blade turning IN???
Remember, I'm learning here but is this configuration odd?

 

[BillyA]

This will not work, the bit on the blade is turning OUT, but the narrow blade is NOT straight across from it.
The one under it will not work either, the narrow blade is in the right place BUT, the bit on the blade is tuning IN interesting for sure.

 

[Rob F.]

Your plug will have a NEMA number on it, you just need to get a receptacle with the same NEMA number.
They are all different depending on the voltage, amperage and phase. The -R at the end means it is a receptacle.

 

[Bill D]

Look here. maybe a bad photo but the ground plug looks like it has a bent out part at both ends?
Bill D.

OSCAR - Misc036 - NEMA Plugs and Receptacles

NEMA Plug and Outlet chart

Need some help identifying your wall outlet? We can help! Below is a description of the more common NEMA outlets and their numbers as well as some handy NEMA plug charts. You can also email us a pic of your plugs and outlets you need help identifying and we would be happy to help. Here are the...

www.bsaelectronics.com

 

[Bill D]

It may be cheaper and faster to get two that match from the bay rather then one special new full price that matches what you have. Especially if you ever want to add another machine and just plug it in.
Kind of like choose cheaper standard inserts so you can buy more for less when needed.
Bill D

 

[Joe Gwinn]

This will not work, the bit on the blade is turning OUT, but the narrow blade is NOT straight across from it.
The one under it will not work either, the narrow blade is in the right place BUT, the bit on the blade is turning IN interesting for sure.

One (or perhaps a few) of those receptacles is correct. There is a NEMA standard telling which to use for what.

Here is the relevant chart:
https://www.zoro.com/resourcehub/understanding-nema-plug-configurations/

And here is too much information, for general background:
https://en.wikipedia.org/wiki/NEMA_connector

Added note on how to connect the twist-lock. You are probably using a NEMA L14-30R mated pair. The crooked blade is the safety (green) ground. The RPC and motors are wired in the Delta configuration (not the Wye configuration), so there is no power neutral (white) wire. The other three terminals are the three phases (traditionally but not necessarily Black, Blue, and Red).

https://www.homedepot.com/p/Legrand...4-30R-Locking-Receptacle-L1430RCCV3/100155901

The green ground is firmly connected to the motor (and machine) frame, to provide a path for leakage from the dirty old motor to ground, and so if a motor winding shorts to the frame, or a wire comes loose, it will pop a breaker, not the operator.

Added another note: The connection to the motor frame must be mechanically secure - typically a crimped ring terminal screwed to the frame somewhere. It cannot be stranded wire wrapped around a screw that is then tightened. Likewise inside the connectors.

 

[Joe Gwinn]

Most VFDs offer no braking or very limited braking. That's because braking require resistors and VFDs - a tightly packaged product - don't have room for them. Some VFDs, like the one I have, offer the ability to add-on external resistor banks that provide 'real' braking.

But, for most machine tools, it's a wank rather than an actual need. On my lathe, it will slow down all by itself fast enough...and if I want it to slow down faster I use the foot brake which is far more effective and versatile. Imagine that....a modern electronic gizmo that is less useful than a 100 year mechanical gizmo.

People who need VFDs for braking are the people doing things like conveyors or mine shaft lifts or precision automation. Manual machining? Very seldom.

Not so. I very much needed braking for my lathe, to absorb the energy in a big chuck spinning. Before I added the braking resistor (and got the VFD configuration correct), the VFD would error out every time I switched from Fwd or Rev to Off.

The mill would trip the VFD, but much less so, likely due to energy stored in the motor, but if the spindle was configured for high rpm, the spindle would store enough energy to matter.

There are plenty of generic braking resistors available; one need not use only those made by the VFD maker. Just match the resistance and power capacity.

 

[just Dave]

The ebay price of $324 also has free shipping. It's the exact same part number and I don't know what shipping is on there website but no use in finding out in my opinion.

North American is a great company to work with. Because the way you remember that machine working so vividly I think you would be disappointed with Anything less than RPC quality power. I have a PL-25, best money I ever spent.

 

[BillyA]

Look here. maybe a bad photo but the ground plug looks like it has a bent out part at both ends?
Bill D.

OSCAR - Misc036 - NEMA Plugs and Receptacles

NEMA Plug and Outlet chart

Need some help identifying your wall outlet? We can help! Below is a description of the more common NEMA outlets and their numbers as well as some handy NEMA plug charts. You can also email us a pic of your plugs and outlets you need help identifying and we would be happy to help. Here are the...

www.bsaelectronics.com

Interesting, thank you! It's a bad photo on my part, it only has the bend on one end.

 

[BillyA]

North American is a great company to work with. Because the way you remember that machine working so vividly I think you would be disappointed with Anything less than RPC quality power. I have a PL-25, best money I ever spent.

Thank you, I'm pretty sure I'll go with North American and yes that drill press was great at work and I'm sure it'll be excellent in my small shop at home. Even if I never personally used it before, it will be ashamed to see it go into a scrap bin but I have used it and I did like it so it just had to come home with me and it was free.

 

[GregSY]

Before I added the braking resistor (and got the VFD configuration correct), the VFD would error out every time I switched from Fwd or Rev to Off.

That's a VFD issue, not a machine tool issue. In other words, you 'needed' the braking to alleviate the VFD's inability to cope with back EMF, not for any reason related to the machine tool or its needs. But the resistors are a BandAid, not a solution. If it works, it works, but it's covering a deficiency in the VFD design.

Every day, people are running 10,000HP motors on VFDs and when the motor is turned off, the VFDs don't go into error, nor do they have resistors or any sort of braking.

 

[DDoug]

You doo know that you can change the plug on the end of the cord ?
Maybe electricity isn't for you.