#1
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Need help from 3 phase motor and control wizards
I'm in over my pay grade here and need some help.
The machine in question is an Eckold Piccolo but the question is generic so I have this in the General Discussion forum instead of the Eckold forum. A friend has a 50 hertz 314 with a stock dual voltage motor wired for 415Y 3 phase. Again 50 hz. Here is the motor plate. It's currently running on a 480 3 phase provided by a HUGE converter that costs a fortune to run and everything else for the most part is low voltage. An additional issue is than when pushed, the motor starter trips off. 20210823_114756_compress87.jpg 20210824_102826_compress24.jpg 20210824_102643_compress46.jpg 20210824_102618_compress35.jpg I attribute this to the motor running 20% faster because it's on 60 hertz. That means 20% more amps too and I THINK the motor starter heaters are not correct. The simple solution would be to change the heaters but there are two issues. 1- we really prefer to run the machine on 240 3 phase because it's less painful and expensive in this case. The low voltage 3 phase converter runs basically all day. The high voltage is 100 feet away and is a 15hp...way overkill. 2- this particular Telemachanics (French company) motor contactor is obsolete. Telemachanics is still around and probably has a low voltage contactor and heaters that will work with the Eckold start, stop, and EMERGENCY off buttons. This is an option. I know how to strap the motor leads for low voltage. I sent photos of the diagrams on the wiring cover to my motor guy and he confirmed what we'd have to do. But the contactor is still 415v? I don't know what I don't know about these things. My 314 manual says the contactor is Telemechanics LC1-D 093. LC1-D 09 is the heater (thermal overload relay). From the photos, I can't tell the load rating of the heater but if we're having the voltage, we're doubling the amp. Plus the 20% extra speed hertz penalty. It seems to me that IF a VFD will handle the contactor issues, we could use a VFD for the start, stop, and speed functions. Set it at 50HZ and the motor will run at factory speeds. Variable speed is a nice enhancement on a single speed Piccolo. I don't know how to decipher the motor tag in the first photo into Horse Power. If the VFD thing is not a viable approach I need to know what to talk to Telemachanics about. My knowledge about this stuff is really low. I'm pretty confident I can install a new contactor and heater or a VFD but I don't want to have my friend buy the wrong thing. Help!
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Kerry Pinkerton |
#2
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I'm not your guy.
I've been using Kent Martins, KMartins@valin.com to recommend VFD's and motors I've purchased for my machines. He's been very patient and helpful. I'm sorry, I don't have his phone number.
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John Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability. |
#3
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Got any better pictures of the motor tag? I sure would love to read the left edge. I think it is saying 1.5 amps at high voltage and 3.2 amps at low voltage. Making some assumptions I calculate the horsepower to be 1.5.
I would tend to lean in the vfd direction. Purely because of the gain of variable speed. Can't help on what heater you need.
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AL |
#4
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Quote:
I think you’re putting too much voltage to the motor, it should be 380 volts not 480, common European voltage! Also you need to check and see what the converter is suppling, 480 Delta or 480 Wye, Delta will have a high leg, the Wye will have three balanced legs? The heaters need to be sized for the voltage used, you can replace the whole contactor with a new one if you can’t find heaters for the current starter? Another option, pull the motor and have it rewound to single speed and the voltage you have available, this solves the problem if the motor is not a standard mount, then use a VFD. One thing to keep in mind with two speed motors, with a VFD you can only use one speed, but the VFD makes up for that! You didn’t mention if this is the only three phase machine, is there three phase at a lower voltage available, if so you could use a step up transformer?
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Kevin. |
#5
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Quote:
20210823_174949_compress93.jpg Here is my friends tag for reference: 20210823_114756_compress87.jpg Note that my machine is 60 hz. Quote:
The issue is multi faceted. 1- High voltage 3 phase is not really desirable in my friends shop although it is available. Long story and not really relevant. 2- Current Contactor and heaters do not work correctly because of the 50 hz thing. 3- Low voltage 3 phase is wired THROUGHOUT the shop and the rotary phase converter runs nearly continually because there are many 3 phase machines (low voltage 3 phase) So the goal is to get this machine on low voltage. Restrapping the motor is easy and I understand and have verified how to do that. I can probably find a correct contactor and heater for the motor BUT, it will still be 50hz and run 20% fast. My KF460 is a 500V 50hz machine. I'm running it at 480V 60hz via a big Westinghouse transformer. It works fine but does run 20% faster than normal. It is a two speed motor and I don't use high speed anyway. The best solution would be a 3phase to 3 phase VFD of sufficient size to run the motor ONCE IT IS CONVERTED TO LOW VOLTAGE 3 PHASE. We don't want to run it on single phase because there are 3 phase (low voltage) drops every 8 feet around the large shop. So I'm looking for information on: Option 1 - replacing the contactor/heater and restrapping to low voltage 3 phase 1- what the motor is in terms of HP and amp draw on low voltage? 2- what contactor and heater would it need and/or who can I talk to that can sell me the correct one? Option 2 - restrapping the motor and going with a VFD 1- does this bypass the contactor. That is, does the VFD perform the same function as the contactor which is nothing more than a big relay with overload protection provided by the 'heater' 2- I THINK the VFD option will bypass all the original start stop controls on the machine. That's not a problem just different buttons to push. 3- what size VFD is needed? I don't know enough to talk intelligently to anyone and don't want to have my friend buy something and it not be the correct one. 4- I've done some internet searching on VFDs and only understand every 4th word.
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Kerry Pinkerton |
#6
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With the rest of the information from your tag I can see your friends motor has a 1.5kw rating, that's 2hp.
You won't need any of the existing control circuitry with a vfd.
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AL |
#7
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Quote:
Can you recommend a reasonable VFD that is correct for this application? That is, as we've now determined, 240V 3 phase input and output and sized for a 2 HP motor. I've heard but don't know that you need the VFD to be 'bigger' than the rated load. We don't need to use a foot pedal for variable speed because we're going to be installing a power downfeed system based on a garage door opener similar to what I put on mine. We'll be using a foot pedal for that function. We will want braking so I guess we'll need a resistor also.
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Kerry Pinkerton |
#8
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This one looks interesting and at less than 100 bucks it's quite reasonable. Its 2.2 KW which might be just enough overkill against a 1.5KW motor.
https://smile.amazon.com/VEVOR-Varia...08KD7NS7P&th=1 89 bucks Amazon Prime. Probably close to 100 with tax. Free shipping. Most the VFDs I'm finding are single phase input and 3 phase output, not 3 phase in and out.
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Kerry Pinkerton |
#9
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If you are going with a known name brand vfd like GE or Siemens or similar you can probably stick with the nameplate rating.
If you are using an unknown or import brand they tend to last longer if you get one 2x or 3x bigger than you need. I'm afraid I can't recommend one brand specifically, most of my vfd purchases have been surplus or auction units.
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AL |
#10
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https://www.wolfautomation.com/vfd-3...-3-phase-ip20/
This one looks nice. It's a well respected brand.
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AL |
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