I have a Leland 6273 3 phase 240 V motor I am trying to figure out how to hook up.
It has 6 black wires coming out of the motor.
It also has 2 much smaller brown wires coming out that were just tied out of the way to the lifting ring. I suspect those were for a tach or possible a heat sensor.
It just has paper labels on the black wires, and they look like they were put on by somebody who tried to figure out the motor in the past. They do not match up with any of the three phase wiring numbers/ letters standards I've been able to find. I want to hook it to a VFD for testing. Since the data plate says it will operate from 6-130 HZ and lists a range of RPM from
96 to 3680 that tells me was probably intended to operate off of VFD in the first place.
Is there any practical way using a meter to determine which wires to pair up to connect to 3 connections on the VFD?
I would use the ohm meter function first to get a better idea of what you have. I suspect you have three windings with both ends of each winding brought out. That would allow you to connect it as either star or delta.
Sounds like there's a good possibility it's been smoked, suggest pull the bells off and take a look...
--if it's a tefc you'll know right off the bat due to the stink.
I wouldn't put anything between the vfd output and the motor except for the cable that connects the two together--no switches no contactors no breakers not even a set of fuses otherwise damage could occur.
I believe Ned is correct with the 2-speed description.
3-phase motors don't have start windings.
It may be worthwhile to determine what the 2 unused wires go to.. they may be a normally closed thermal protection switch/sensor connections (so zero or very low ohms reading), which would be used for cutting the power source when the internal temp exceeds the specific rating of the switch/sensor. Thermal protect connections for a 3-phase motor would typically be wired to the appropriate terminals on the motor drive/VFD.
When attempting to trial run a motor with an unknown history, it's often a good idea to plan for other results besides a perfectly normal motor. Some precautions should always be observed, the first one being to make a clean, secure connection (not just an old piece of speaker wire) to the motor case and connect it to a known good earth ground of the utility electrical system/source.
If not already, a good time to get familiar with the VFD protection settings is before applying power to it.. that generally means having the correct operating manual, and studying it to become familiarized with all of the protection features, how to enable them and what parameters would be appropriate for a motor of unknown history.
Perhaps, but I did provide erroneous data for his initial conclusion. The data plate says 3/130Hz not 6/130.
Some of the reading on that subject is a bit confusing in reference to synchronous motors.
And if Leland was still in business or I had a manual I would find out. I'm not ready to start disassembling the motor as yet. Their connection is not readily apparent with the rear cover off.
Yup, and I would like to make sure I am atleast connecting the motor properly before making a trial run.
The first thing I did was wire in an outlet (PROPERLY) and install a new cord and plug on the disconnect I plan to connect the VFD and motor to when ready. The entire assembly IS electrically grounded.
I do have the correct original factory manual for the VFD, and I have read it a couple times now. Right now I an trying to make sure I don't damage the VFD when I connect the motor.
Likely a heat sensor. Tach wires would probably be differently color coded (assuming a DC tach generator), and would be unlikely on a three phase motor anyway. The motor is going to lock to the frequency (with some slip varying with load).
Skip down to the bottom for other information you posted elsewhere and the changes that apply.
Well ... you can identify pairs of wires with a given winding using an ohmmeter. With 6 wires, it is unlikely to be anything but three independent windings, which can be connected in either Wye or Delta, depending on the voltage needed.
Mark the pairs by something like a piece of different colored tape around each pair, so you can identify the pairs later.
Now -- once you have them set up in pairs, put the shaft in your lathe chuck or something else which can rotate it at a constant speed.
Then apply say 6 VAC (from a filament transformer) to one winding, and declare one end of that winding as "common". Connect one end of each of the others to your common (creating a Wye connection), turn on the lathe, and apply the 6 VAC. Measure the voltage from common to the 6VAC point, to see what you really have (likely near 6.3 VAC instead of the nominal 6 VAC, but note whatever it is.)
Then measure the voltage between the 6.3 VAC point and the free end of the other two windings. If the voltage you get on one of those is less than the 6.3 VAC which you had before, reverse that winding (swap the common end with the free end), and check again. At this point, it should be higher than the 6.3 VAC input with the lathe spinning the motor.
Once you have both of these wired to give you more voltage (you could use an oscilloscope to verify the phase of each winding, but the voltage should be enough of a clue, start numbering the wires, taking your first pair (the one which you were feeding power into) and number the part which joins the other two as '1', and the other end as '2'. Then pick another winding and number its joined end as '3', and the free end as '4', and finally the last with the joined end as '5', and the free end as '6'.
You can now use it as wired -- if it is intended to be a "Wye" connection. Measure the current in Wye and Delta configurations with no load and pick the lower of the two (not as close to saturation) as the one to use with your 240 VAC from the VFD.
If you want Delta, hook '2' to '3', '4' to '5' and '6' to '1'.
Note -- I don't know whether this numbering will match what you will find in books, but as long as you use only it and what I have described, you should be able to make things work.
Instead of using the lathe to spin the motor, and using low voltages for safety, you could apply say 120 VAC to one winding, and give the shaft a spin with a rope to start it, and measure your voltage relative to 120 VAC -- just be much more careful.
Hmm ... looking on the web. I find other places where you asked the same question, and on one you say:
====================================================================== The wires are in groups of 3. Any 2 in the first group read about 20 ohms.
Any 2 in the second group read about 2 ohms. ======================================================================
Which suggests that the three which measure 2 ohms are likely the three phase power input windings, and the other three are perhaps feedback to some kind of controller other than the standard VFD. What happens if you connect the first three to the outputs from the VFD. (This is assuming that both sets of wires are the same gauge. If the ones to the
20 Ohm wires are heavier, apply power to those instead, but at 5 HP, I doubt that this will be right. If it as I now believe, just cap each of the 20 Ohm wires to protect them from shorting into anything.
Does it matter which order I hook them up in then? It was my understanding if you just had the three wires all you had to do was hook them up and if the motor ran backwards you just swapped any two wires. (unless the VFD has reversed the motor for you)
I have not hooked up the VFD or the motor yet. Still doing my homework. All I did today was setup a 240 V disconnect with a short 10 gauge cord and a locking plug, then installed a receptacle with a matching outlet. That circuit was intended for my future air compressor, but it will work for this for now. Oh, I did also order a frequency meter to hook to the VFD for testing. I couldn't find my old Radio Shack meter with the frequency counter.
They are the same gauge.
What do you think about the thought that it might be a two speed motor?
I'll probably use a momentary switch for the start switch on the VFD for testing, and keep a fire extinguisher handy. I need to pick up a 2w 1k POT for frequency control for now too. The VFD will be setup with 0-10 VDC control eventually, but for now its going to be setup for variable resistance control.
Good recommendations, as usual DoN. I thought about commenting on low voltage testing, but left it out considering that Bob was getting good info.
Just connecting a low AC voltage to any winding should provide useful/noteworthy results in testing induction motors with multiple windings, since the separate windings share the same ferrous frame/core.. in much the same way of connecting a low AC voltage to a transformer will always cause some detectable output on any good windings around the core. The noted results information may take some further head scratching/pondering, but will lead to reasonable conclusions.. even without spinning the rotor.
For unmarked leads, one definitely should use some arbitrary markings to retain any sanity while trying the testing.. paint colors, temporary letters or any markings are better than trying to keep the leads sorted while testing.
I'll add that for some DIY types, it may be possible to use a low setting on a variable speed drill to spin motor rotors or armatures (or in generators), and a precise coupler isn't needed.. the coupler can be a piece of automotive heater hose with a plug and a bolt in one end, or similar improvised gizmo.
There are a lot of testing procedures for motors, often covered in better motor books which will generally also include descriptions of different types of winding schemes and standardized lead numbering patterns. Other types of 3-phase motors with more than 6 leads are often much more difficult to decipher if there are none of the original wire numbers to be found on the leads. Opening the case may reveal the wire numbers inside, but otherwise most folks would need to have a motor shop sort out the lead numbers.
As far as checking the two previously unused leads, it depends upon how the meter being used for the test behaves when checking a zero ohm connection.. many DMM meters may consistently display up to about 7 ohms with the lead tips pressed together.
Whatever the meter shows with the tips pressed together is zero then, for that meter.. (assuming the connections are clean and snug at the other ends of the test leads), so if that reading is displayed while checking those 2 leads, then the internal device is most likely a thermal protection switch/sensor.
These types of switches are generally the bi-metal/Klixon type and when their specified temperature is reached, they open (infinity ohms) until the internal motor temp cools to a level where the contacts close again.
Some inverter rated motors have a separate fan motor in them. It could be that you have 3 wires for fan (probably the 20 Ohm set) and 3 wires for the motor (the 2 Ohm set). You can connect the VFD to the 3 low ohm wires and power it up at a low speed, maybe 6hz or so. Also try the drive on the 20 Ohm leads, again try at low speed.
The problem with running a VFD rated motor at low speeds, down to 3hz, is that their fan isn't turning fast enough to cool the motor. So you run a power to the fan at rated line speed and power to the motor through the VFD. I would think a motor rated down to 3hz would be equipped with a small cooling fan motor. I guess the easy way to check is to turn the fan and see if the shaft turns.