VFD setup

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liveaboard
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Re: VFD setup

Post by liveaboard » Sun Oct 27, 2019 3:03 am

Thanks, I understand the vfd has to do the reversing if the VFD is in use; what I meant was that if it doesn't perform as I want, I won't use it for the lathe at all. I've rewired the old reversing switch to use as a control switch for the vfd.

I have the lense instructions; Patio's link is easier though, I wish I'd seen that earlier.

I can only see the motor plate with a mirror, and I'm not 100% sure I have the numbers right. Maybe I have to remove it to read it properly, that seems a bit radical.

It will brake successfully from a low speed. I'll try increasing the brake ramp time, but if it's more than 3 seconds then I don't think it's very useful.

After I get it working on the lathe, I'll try switching it to the drill; for the drill, speed control is the fun part, braking and quick reversing isn't required.
If it won't drive both, it's ok. If it will, that's better.

I didn't think it would be this difficult.

RMinMN
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Re: VFD setup

Post by RMinMN » Sun Oct 27, 2019 5:23 am

If you have a smartphone or tablet, take a picture of the motor plate. It's easy to flip the picture so you can then read it. You can even magnify the picture to make it easier to read.

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liveaboard
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Re: VFD setup

Post by liveaboard » Sun Oct 27, 2019 7:56 am

Tried that, no success. I will try again after lunch; it's really hard to get a light, a mirror, and a camera on it at the same time!

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Re: VFD setup

Post by liveaboard » Sun Oct 27, 2019 1:22 pm

I managed to get a picture of the motor plate; that was a waste of time.
zelenda uz4 motor plate.jpg
It makes no sense at all; 5.2 amps at 380 v would be 3 kw, the plate states 1.3kw
As you can see, it's a 2 speed motor, I'm only using it at high speed.
And it's sure not 4HP.
PK means horsepower in german

So I tested the current with a clamp meter; 2.1A, rising to maximum 2.4 at heavy load [enough to slow the motor].
If you look closely, you can see the volts have been scrapped off.
So I assume the motor was re-wound sometime in antiquity. Could it have been a 180V motor? has there ever been such a voltage?

Resetting the amp parameter on the vfd had no effect anyway. When I increased the stop time from 0.5 to 2 seconds, it works ok.
It doesn't stop in 2 seconds, but it's ok.

I haven't go the control wiring to work how I want yet; it seems the VFD electronics like momentary signals to tell it what to do, not a continuous one like I get from the old switch on the lathe.
I'm hoping to solve the problem with a couple of jumper diodes.

Switching it over to the drill press works just fine.

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Re: VFD setup

Post by Patio » Sun Oct 27, 2019 8:10 pm

Liveaboard, the VFD will work with momentary or maintained contact type switches. Page 32 in the manual has three different switch set ups. The one in the middle is a momentary system and the two on each side are maintained type contacts.
How is the switch you want to use configured? Are you using one switch for FWD/REV with a middle stop position? Is there a run/stop switch with a FWD/REV switch? Depending on what you have, depends on the set up. They are pretty versatile systems.
Here is a link to the manual if anyone is interested.
http://download.lenze.com/TD/ESV__SMV%2 ... -0__EN.pdf
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Bill Shields
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Re: VFD setup

Post by Bill Shields » Sun Oct 27, 2019 9:23 pm

originally would have been:
delta / star, 50 cycle = most likely 380 - 400 volt (originally)
Netherlands => no earlier than 1936 based on logo on nameplate (is lathe that old?)
PK = paardekracht in dutch which is the same thing (paard = horse) 1 horsepower (3/4 KWatt) / 1.75 HP

2.4 amps at a heavy load sound suspiciously like you have the wrong voltage (depending on your definition of heavy load since the nameplate lists 5.2 amps).

Is there a way that you can get the vfd to display current instead of RPM???

Have you checked actual loaded motor RPM to indicated RPM on the VFD ????

Motor could have been made for Dutch Export to anywhere, however in Europe..most of which has been 400 V 3 phase for a long long time.

why it would have been rewound for a different voltage is a real head scratcher..although some large companies (at least in the USA) had their equipment running on odd voltages to keep people from 'helping themselves' to motors and whatnot by making them incompatible with 'grid voltage' outside of the company power system.

reversing is done in all cases by the drive....

if, using the buttons on the VFD itself you can get it to start forward / stop / start reverse / stop you are on your way..
Too many things going on to bother listing them.

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Re: VFD setup

Post by liveaboard » Mon Oct 28, 2019 3:39 am

Patio, that's great. I don't know how I overlooked that page.
The switch I'm trying to use is forward/off/reverse so it should go easy now. It's just because the switch has a nice big lever built into the lathe and I'm used to whacking it without having to look.

I also found that info about the motor, made in the Netherlands between 1936 and 1974.
I bought the lathe in the Netherlands; it's not a common machine, "Zelenda" Czech made. This is a metric version, they made inch ones too. I don't know the age of it.
I found 2 sets of pictures of the same lathe, posted on a Czech website. Each has a different motor; one of those is 700 / 1400 rpm like mine, which matches the plates on the lathe. Those are German AEG 3-phase 380V motors. No doubt, a buyer would order the motor to match his power supply.

I'm not really good at this, but from my calculations of the other values, the volts work out to 180, and the plate looks like it might have had 180 stamped on it.
Just out of curiosity, I've been trying to find out if 180V 3-phase was ever used anywhere; I haven't found anything on that, but I did once have a 3-phase connection in Amsterdam that was pre-war wiring and was supposed to be 220v. in reality it was around 205-210 between legs. It was the remnant of a historic 110v service. The supply wires were terrifying. It was finally replaced in 2010.
A lot of 3-phase machines sold in the Netherlands had a 220v delta option due to these legacy power supplies [this is the sort of conversation I have with people I meet].

The motor on my lathe is old; the cast iron pulley is damaged, which indicates it has been removed at some point. It looks heavy, a new motor this size would be at least 5HP.
If the motor was supplied to operate at a legacy voltage for it's first owner, then when that power supply was upgraded there would have been 2 possibilities, rewinding the motor or replacing it. Rewinding would have been cheaper than replacing before [say] 1980.

Whatever, the amps on the plate bear no relation to the motor as it is now, so I'm using real measurements, which is 2.4A. I noticed the primary drive belts are slack so I'm going to tighten them and measure again.

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Re: VFD setup

Post by John Hasler » Mon Oct 28, 2019 9:54 am

I read 280 but it looks to me like it's been restamped and then scraped. I think I see the remnants of a "1" to the left of the "2".

Star connected 480 is 277 phase to neutral. That makes no sense to me on a motor nameplate, though.

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Re: VFD setup

Post by liveaboard » Mon Oct 28, 2019 1:27 pm

Ok, after tightening the belts I re-measured the current while running on 3-phase, 380V mains [actually, 410V].
As before, 2.5A - 2.7A when loaded, but now it cuts like a demon.

After setting the parameters and switch wiring as directed in the page Patio found for me [which I had printed out but not noticed], it's a happy machine.
I've now added a speed pot and set the max speed at 100Hz, double the motor design spec; it sounds a bit exciting at that velocity, but the armature stayed together.

Despite being calibrated for the 1.7 HP 1400 rpm lathe motor, when I connect it to the 940 rpm 2hp drill motor it works the same.
Tomorrow I'll connect them with a selection switch. The Drill will have it's own forward / stop / reverse switch but the speed pot is shared.

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Bill Shields
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Re: VFD setup

Post by Bill Shields » Mon Oct 28, 2019 2:27 pm

be careful about running the lathe at low speeds at a heavy load.

Many old motors cannot handle it and may well likely overheat..

in general, a VFD is not a replacement for spindle speed gears.

Your comment about the 'armature stayed together' has more truth than you may realize...

in reality, the same rotating iron may well have been produced to run at 3000 RPM...but you never know...and a bar that comes loose can be truly exciting.
Too many things going on to bother listing them.

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Re: VFD setup

Post by Patio » Mon Oct 28, 2019 3:02 pm

Bill Shields wrote:
Mon Oct 28, 2019 2:27 pm
be careful about running the lathe at low speeds at a heavy load.
Many old motors cannot handle it and may well likely overheat..
This is true.
One can install a cooling fan on the motor that activates when the motor does or with a temperature sensor.
One of these day I will run a temperature test on my lathe, while running under the native speed, to see how hot my motor may be getting.

Glad you got yours running like you want it to.
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Re: VFD setup

Post by liveaboard » Mon Oct 28, 2019 3:36 pm

Thanks guys, and thanks for all the help and tips.

I have some little electronic thermometers with sensor on a wire; I was thinking to use one to keep an eye on the motor temp.
It's a very large frame motor, which should be good for cooling.
Not so good for overspeeding.
It still has 3 gear ratios.
If you double the speed of a spinning body, how much more force is trying to pull it to pieces?
Is that double too, or is there some terrible multiplication factor?

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