Friday, January 1, 2016

Vitamix blender motor repair

Windings on motor rotor were damaged, I think the chaffing on the insulation led to a breakthrough and subsequent failure.

I had to completely unwind the rotor and rewind it with the same diameter enameled wire (the damage was on one of the innermost windings). Here we have a 220V mains, so the motor might be slightly different from the more common 110V US units.

Blender is pretty old, Vitamix wants a serious chunk of $$$ for a replacement motor. Admittedly I had to spend quite a bit of my free time to get this fixed, but it really only cost me $40 in raw materials.

IPC_thumb

Breakdown of the vitamix blender. Should've taken more photos.

69848-1_thumb

What a new motor will look like, inside is essentially an open frame universal motor.

20151117_181207_Richtone(HDR)_thumb

The rotor out of the motor and me unwinding motor. I had to remove the center insulation pieces all around and document how each winding was interconnected.

20151117_181009_thumb

Another shot of the old windings.

Diagram

I drew a little diagram to sort out what goes where. The motor had 22 commutator segments and the same number of slots for the wires to wind around. Each winding was 22 turns of enameled wire.

20151204_221626_Richtone(HDR)_thumb

The motor partially wound, I elected to solder every end onto the commutator for a more reliable electrical connection.

20151205_100915_Richtone(HDR)_thumb

Cleaning the completed motor to prepare for application of red enamel.

20151205_200359_Richtone(HDR)_thumb

Red enamel applied on one side.

940952_10153297856048870_1049039112378700865_n_thumb

The original bearings on the rotor were made by NMB, 608SS. SKF does the 608RS that's also a rubber sealed bearing.

20151230_141343_Richtone(HDR)_thumb

After the enamel has cured, this is what the rotor looks like.

20151230_141550_Richtone(HDR)_thumb

Replacement bearings side by side with the existing ones.

20151230_150104_Richtone(HDR)_thumb[1]

I had to grind and cut off parts of the bearing to remove it piece by piece to get them in. There was insufficient clearance to pull them off.

20151230_150206_Richtone(HDR)_thumb

Bearing inner race still left on shaft, for this challenging location I ground 2 flats on the inner race and used a vice to apply pressure until the inner race cracked and separated from the shaft. Usually this works quite well because the races are super hard.

20151230_155720_Richtone(HDR)_thumb

Replacement bearing now on.

20151230_161038_Richtone(HDR)_thumb

Motor assembled together, sans the 2 brushes.

20151230_163345_Richtone(HDR)_thumb

Motor assembled into the blender.

20151230_163544_Richtone(HDR)_thumb

The ass end of the motor/blender. A plastic impeller that moves air for cooling the motor goes here.

20151230_165346_Richtone(HDR)_thumb

The blender finally together. It was tested out and it really kills ice cubes (we tried blending a bunch of ice).

On a side note. Happy new year everybody wlEmoticon-smile[2] 2015 went by really fast for me, here’s to 2016.

Update: 17th April 2016

The Mechanic has kindly went ahead and did up a professional looking diagram of how the motor is wound up. I hope the motors he has get fixed.

vitamix-crosssection-full

Note that the commutator is not shown in the top down view, only the windings are.

8 comments:

  1. can U show a diagram of how the the on/off-hi/lo switches were wired ? thank you

    ReplyDelete
    Replies
    1. I don't have the blender with me now, but if you take a picture or draw a diagram of what you have now I think we'll be able to figure that out.

      I only pulled the required wires away to get the motor out. So that means disconnecting the 2 brushes as well as some of the overheat protection circuitry.

      Delete
  2. This comment has been removed by the author.

    ReplyDelete
  3. Hi I am trying to unwind my vitamix motor. Do you have a higher resolution image of your diagram? It might help me complete mine. Thank you! Any tips on winding?

    ReplyDelete
    Replies
    1. I have updated the post with the original scan of my crappy drawing. Basically I just marked one section of the commutator (and that's what I defined as the 1st commutator). I can't remember exactly which slot on the armature I marked as 1st, because it's been awhile, it should be the 1st slot to the right directly under the commutator I marked as 1.

      I don't know if the diagram is of any help to you, it will probably help if you have some remaining windings left over that you haven't removed to take reference from, your motor might actually be completely different from mine.

      Wind the coils as tight as you possibly can, especially at the start, as it approaches the end, it gets increasingly difficult to keep it all within the space provided because they will all overlap at the top and bottom of the armature.

      Delete
    2. Thank you so much for the diagram. I have taken the liberty and created a full blown diagram and would like to send it to you to make sure that it is correct. I do have an original motor that I have yet to unwind but was waiting to understand a bit more before taking it apart. I would like to be able to send my diagram to you. please let me know where I can send it. thanks!

      Delete
    3. You can send it to me via Email at fox3.aim120ATgmail.com

      I'll look it through and see if it's anything similar to mine.

      Delete
    4. Ok, sent. If you dont see it in your inbox, look in your spam.

      Delete