Lagun motor jumper configuration

R Thor · Oct 24, 2020

I am new to the forum and I am not sure what the best group is to post my question. If there is a better group to post this question please let me know.

I need some help from someone with an 80's era Lagun mill with a 2hp motor. I am not electrically astute but have an electrician friend helping me to install a VFD on this mill. We are not able to confirm if this mill is configured for low or high voltage (240 or 440). Besides the motor name plate (pictured below) there is no other labeling. If there is anyone that has this motor on there mill and you are running at 240v would you be kind enough to take a picture of how the jumpers are configured. Any help is greatly appreciated.

Rick

jmullett · Oct 24, 2020

That motor is set up as my Lagun knee mill is running 480 volt (HIGH VOLTAGE) 3 phase supply. I am attaching a photo of the inside cover on my terminal box of the Lagun motor. You need to move the jumpers to join the three farthest from the line connections to set it up for 240.

R Thor · Oct 24, 2020

jmullett said:
That motor is set up as my Lagun knee mill is running 480 volt (HIGH VOLTAGE) 3 phase supply. I am attaching a photo of the inside cover on my terminal box of the Lagun motor. You need to move the jumpers to join the three farthest from the line connections to set it up for 240.

View attachment 302772

Are you saying I should be connecting terminals 7 to 8 and 8 to 9 as per the image below.

jmullett · Oct 26, 2020

First the numbering convention you used for the lugs is a bit unorthodox to what is normally shown in diagrams. I've edited the picture and renumbered them. Also including a diagram of how those terminals are connected to the motor windings internally.

Motor Jumpers Drawn in for Low Voltage.jpg

Using my numbering system you should be able to ohm out the windings (WITH ALL JUMPERS REMOVED) and see that it is a WYE wound motor.

The ohm readings on my 2 HP REIVAJ brand motor on my Lagun FT-1 mill are as follows:

1-4 3 Ohm
2-5 3 Ohm
3-6 3 Ohm

7-8 6 Ohm
8-9 6 Ohm
7-9 6 Ohm

Open circuit on any other combination.

Here is a couple nice videos with a good explanation of the windings and low vs high voltage connections.

Dual Voltage, 3 Phase, 9 Lead Wye Motor Connections #1 - YouTube

Dual Voltage, 3 Phase, 9 Lead Wye Motor Connections #2 - YouTube

Don't forget you need also to change the wiring in the coolant pump motor in the sump to the appropriate voltage..

R Thor · Oct 26, 2020

jmullett said:
First the numbering convention you used for the lugs is a bit unorthodox to what is normally shown in diagrams. I've edited the picture and renumbered them. Also including a diagram of how those terminals are connected to the motor windings internally.

View attachment 302936

View attachment 302937

Using my numbering system you should be able to ohm out the windings (WITH ALL JUMPERS REMOVED) and see that it is a WYE wound motor.

The ohm readings on my 2 HP REIVAJ brand motor on my Lagun FT-1 mill are as follows:

1-4 3 Ohm
2-5 3 Ohm
3-6 3 Ohm

7-8 6 Ohm
8-9 6 Ohm
7-9 6 Ohm

Open circuit on any other combination.

Here is a couple nice videos with a good explanation of the windings and low vs high voltage connections.

Dual Voltage, 3 Phase, 9 Lead Wye Motor Connections #1 - YouTube

Dual Voltage, 3 Phase, 9 Lead Wye Motor Connections #2 - YouTube

Don't forget you need also to change the wiring in the coolant pump motor in the sump to the appropriate voltage..

Thank you very much I really appreciate your help. Carmen at Lagun sent me a diagram of the proper jumper configuration for 240V and it is exactly as you have shown above. I am now up and running. I bought this mill and it wasn't in great condition. I disassembled most every part of the mill, cleaned, painted and repaired. This took a long time. A friend of mine gave me a VFD and helped me to configure it. I am not electrically savy. When we powered up the VFD we kept getting line fault errors when we turned the spindle on. My friend thought the machine was wired for 440 but was confused due the numbering scheme on the winding wires.

Now the mill is running great and I can finally make some chips. Thanks again for your help.

R Thor · Oct 26, 2020

Thank you very much I really appreciate your help. Carmen at Lagun sent me a diagram of the proper jumper configuration for 240V and it is exactly as you have shown above. I am now up and running. I bought this mill and it wasn't in great condition. I disassembled most every part of the mill, cleaned, painted and repaired. This took a long time. A friend of mine gave me a VFD and helped me to configure it. I am not electrically savy. When we powered up the VFD we kept getting line fault errors when we turned the spindle on. My friend thought the machine was wired for 440 but was confused due the numbering scheme on the winding wires.

Now the mill is running great and I can finally make some chips. Thanks again for your help.

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