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Help rewiring motor from 460 to 208

Damon73

Plastic
Joined
Oct 26, 2020
I have a leeson motor that is 208-230v and 460 and I believe it is currently wired for 460, on the name plate it looks like it tells you how to wire it to 208 but there is three lines coming in so which one would be the neutral?
 
I have a leeson motor that is 208-230v and 460 and I believe it is currently wired for 460, on the name plate it looks like it tells you how to wire it to 208 but there is three lines coming in so which one would be the neutral?

No neutral, just 3 hot wires. Follow instructions on data plate, if rotation is incorrect swap any 2 power leads.
 
...I guess I know less then what I thought... So I have 3 phase but between 2 lines I have 208ish volts, how can I connect 3 wires and not fry the motor? Here is some pictures of it now that I am on a computer and can upload them.IMG_20201026_145514.jpgIMG_20201026_145602.jpgIMG_20201026_145558.jpgIMG_20201026_145552.jpg
 
...I guess I know less then what I thought... So I have 3 phase but between 2 lines I have 208ish volts, how can I connect 3 wires and not fry the motor? Here is some pictures of it now that I am on a computer and can upload them.View attachment 302967View attachment 302968View attachment 302969View attachment 302970

Any line to neutral will give you 120v, Any line to line will measure 208V, UNLESS there is a high leg, in that case the high leg to either of the other 2 legs will give you 250ish?? voltage, been a while since I had that, and I'm not a sparky.

You should have 4 wires going to motor, L1, L2 and L3 and ground, ground connects to case of motor, follow directions on data tag to rewire for 208v.

Here is another post, same issue, more pics, might help you understand
Lagun motor jumper configuration

If you do not understand, ask again, or find a sparky that is familiar with 3ph.
 
All this will usually be found in the connection box ON THE MOTOR - often referred to as the "peckerhead"

A dead give away on being "connected" for high volts is that the three "line" wires will be connected to three T wires coming out of motor

Low volts connection uses a PAIR of T wires for each line wire

The tag on the motor shows you exactly what the rest of the low volts connection does with the NINE T wires

Each T wire has its own identifying "tag" - though these may be hiding under blobs of electrical tape

Any thermal overloads will need to be replaced with suitable double the amps rating compared to running motor on high voltage

My first "rentashop" (1977) had 208 three phase - the 220/230/240 volt machines seemed to care less
 
I'm confused but that's how they are wired, the only issue I have now is what do I change on the box(3rd picture) to change it from high voltage to low as shown in the 2nd picture(bottom right corner).
 
To get that setup to work properly you need three things.
Rewire the motor connections as shown on it's label. Find the T labels printed on the wires.
Replace the overload relay and starter to handle twice the current 8.4A @ 460 to 17.6A @ 208V
Change the voltage input jumper straps on the control transformer from 480V to 230V and likely the input fuses as well.

Short of that your likely to have issues.

Look at the print, it shows how to rearrange the jumper straps on the control transformer.

SAF Ω
 
Was hoping it was just switching the wiring, so I got the first part and the 3rd(need to pick up some fuses), I didn't notice jumper across 2-3 until I looked at it closer. So just making sure, it wouldn't have a overload relay and starter that's rated for 17.6A? If it is possible how can I check and if not is there one you would suggest(I don't want to get the wrong one). Sorry I am such a newbie but would a vfd be able to replace any of the parts I need?
 
The photo of the contactor, appears this has an adjustable current trip.
contactor.jpg
The wires that leave this current trip appear to be too small for the current at 208VAC for a 7.5HP motor. If I'm reading the name plate, it's 18.8 amps. These should be 12AWG copper, to operate, check them for size.

And no, a VFD will just complicate this change over at this point.
 
Made you a show and tell

IMG_20201026_145552.jpg

You will be changing this lash up to the low volts diagram on the motor - if you want to run on low volts

Or..there is always the transformer approach - such as a 10 KVA Three Phase Dry Type General Purpose 480 / 240. The new one I bought so long ago was a step down that the maker (ACME) approved for step up use and its has worked with no problem since 2003
 
Ya all the thin wires are 14 gauge, fuses are 3/10. The contactor is a Moeller DIL00AM-10 and the overload relay is a Moeller Z00-10, what should I be getting to replace them?
 
Already had the wires done last night, tested it just to make sure everything worked since with no load it shouldn't be pulling many amps and it turned on fine. What about the contactor/starter, should I just try to find a Moeller like KLOCKNER MOELLER DIL 1 M CONTACTOR 31 DIL M MURR ELEKTRONIK 20010 #10G101RM | eBay ?


That would give you 10HP contacts. You need an overload trip for the motor. I'm not familair with this brand, but I think the heaters are in the top 'blob' on the contactor. They would have to be sized for the 18.8FLA of this motor at 208VAC input. I think you said that was your input power system.
 
I was saying in addition to the overload relay. The starter/contactor I have is only rated for 3 hp @ 230v. There is the Moeller DIL0M which is good for the 7.5hp but at 230v not sure at 208v so I was thinking go one size bigger but since I was not sure that's why I was asking if its what I need.
 
What do you mean would give 10hp contacts? is that ok or no? if the DIL0M is what I need I can buy that. Heater... not sure what that is but if your talking about the thing on the link I shared from ebay I was thinking I could just remove that part or buy another DIL1M since I don't see one on my existing set up unless I need one? My input is 208VAC. If anyone knows one from a different brand that would work, I am not sure what I need so I was searching for a bigger size from the same company. I cant really tell what everything is, so I am going off of assumptions which so far has not been good :( any help is greatly appreciated
 
What do you mean would give 10hp contacts? is that ok or no? if the DIL0M is what I need I can buy that. Heater... not sure what that is but if your talking about the thing on the link I shared from ebay I was thinking I could just remove that part or buy another DIL1M since I don't see one on my existing set up unless I need one? My input is 208VAC. If anyone knows one from a different brand that would work, I am not sure what I need so I was searching for a bigger size from the same company. I cant really tell what everything is, so I am going off of assumptions which so far has not been good :( any help is greatly appreciated

Yes, 10HP exceeds the 7.5HP of your motor.
Heaters are used in contactors that are not adjustable, but fixed to the motor size and current rating, you need 3 of them for 3 phase. Your old contactor had the adjustable current trip, but was limited to 10 amps. That's why everyone is pointing you in a replacement contactor.
I would look for the 20 amp model (or larger that supports 7.5HP at 208VAC input), with the 20 amp (or larger, as long as 18amp is in it's adjustment range) adjustable current trip, similar to what you have now, but larger current rating.
 
Yes, 10HP exceeds the 7.5HP of your motor.
Heaters are used in contactors that are not adjustable, but fixed to the motor size and current rating, you need 3 of them for 3 phase. Your old contactor had the adjustable current trip, but was limited to 10 amps. That's why everyone is pointing you in a replacement contactor.
I would look for the 20 amp model (or larger that supports 7.5HP at 208VAC input), with the 20 amp (or larger, as long as 18amp is in it's adjustment range) adjustable current trip, similar to what you have now, but larger current rating.

I cant seem to find any that say anything about 208v only 230v from that company, isnt the part that has the adjustable current trip a separate part from the contactor? I was thinking to buy the one you linked and put it onto the contactor like my current set up. Sorry about all of this, when I look at this stuff I have no clue what does what.
 








 
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