April 2020 SARebuild 18 Traction Motor

28 MAY 2020 After the last motor problem I have modified the armature shaft replacing the inner stupid circlip with a steel sleeve spacer for the 50/90 x 30mm bearing. The aim of this is to limit the end float.
Mods to the gearbox casing are to drastically increase cooling air flow.

 This rotates at 6000RPM at 60MPH

 Running a constant 55MPH causes an unintended pumping effect in the gearbox. This eventually pumps all the oil out to the near side wheel the gearbox will eventually run dry!

 Mods to the field winding are to thoroughly clean it with white spirit - dry it then saturate it in clear varnish - something the manufacturer didn't do for some reason

 Tape up the field winding wires to help pull them through - helps re assembly

 50mm thrust washers replace non extant thrust washers in the original

124024 miles. Another breakdown on the M4 East J6 I'm sorry to report. I was in the section without hard shoulder when the motor again cut out! I needed to call the AA for emergency recovery. (it took 4 hours) 30-1-2020
When I got back I removed the motor again and pulled off the ends. The circlips restricting the armature shaft end-float had worn away a section of the shaft allowing the windings to come into contact with the gearbox casing. This shorted the armature windings destroying them!

Brush holder worn away due to armature end float

SEPTEMBER 2019 TWO MORE BREAKDOWNS REQUIRING AA RECOVERY

9th September 10 PM Battery Voltage suddenly dropped to 134V travelling west on the M4 just opposite Slough sewage works. Recharge and STOP lights came on - I had to pull onto the hard shoulder and call the AA it took until 2:30 am to finally get home via 2 car transporters.
I put the cause down to low electrolyte in a cell (dry) . I refilled all the batteries and all seemed well until 30 September. I was driving towards Gerard's Cross when I smelt burning - I couldn't see the smoke because it was dark. However on the hill the traction motor cut out and the headlights went very dim. I used a torch and saw the cabin was full of smoke! One cell in the TOP battery under the bonnet had completely burnt out near the top. I tried refilling it with water by the roadside but it only lasted 2 miles before it cut out again this time the traction battery voltage went to ZERO. Corrosion in one cell disconnected it ! I got another tow home and replaced the open circuit battery. Everything went back to normal.

>100000 Mile Report Berlingo Electrique 26 July 2018

1) Ten  STM5-100 Batteries died over the last year , one cell per battery
2) The traction motor problem is resolved - 1.5 x 0.5inch brushes have replaced the 1 x 3/8 inch
3) 75W DC axial fan has replaced the original weedy centrifugal fan
4) The fan now sucks hot air out of the motor rather than blowing
5) A big hole has been cut at the top to maximise air flow
6) Water refills are now more frequent at 1000 miles - these are dome BEFORE charging to maximise fluid level - electrolyte loss has been found negligible as long as overcharge is prevented.

 7) Double Berylillium springs replace the old week steel ones

 8) Left is new brush, right are the same with 12000 miles wear

 9) The new brushes are also longer !

 10) The new neutral point must be acurately set to avoid commutator destruction - due to shorting

 11) You can see in this image how much metal I removed from the housing to accomodate the larger brushes
12) The commutator width is maxed out now

Now over 91000 miles traveled. Two more breakdowns requiring AA recovery both due to brushes getting stuck in their holders. I am now working on replacing the 25 x 10 mm ones with 11/4 x 1/2 inch (60% larger area. This is to reduce the rapid heating of the brushes causing the brush tails to pull out. A lot of the existing size brushes failed early due to wires pulling out of the carbon block.

Traction battery charger module burnout.  

One night the battery didn't charge. After checking the fuse in the plug I followed the power back to the charger module within the large ECU. I removed the module and discovered the mains input choke had burnt out. 

The reason for the burnout is too little copper around the pad. The pads unaffected were to copper planes. To fix it I have made a direct link to the plane using the winding directly.

LESSONS LEARNED AFTER 9 YEARS HEAVY USE

1) Refill the batteries every 2000 miles
2) Check condition of brushes and commutator every 2000 miles
3) If you are planning to go on a motorway you need to remove the traction motor and fully open up the air inlets on both sides using a hammer!
4) Fit a small DC fan directly above the charger module within the ECU, see earlier picture
5) If you run out of charge (yellow light on) find a place to stop and call for a tow (or you will blow a cell)
6) If you are using motorways try to keep the speed at 60 Max (higher speeds cause the commutator to arc severely)
7) Use Evan Tuer's device to reset the water light when it comes on (or you wont be able to put in 100% charge) this is a serious problem because the individual cells will get out of balance and burn out.

Good Luck

Big Problems With Berlingo Electrique at 71086 miles

In the last year I have replaced the traction motor again. This was necessary because the motor shorted out between commutator and chassis. Shorting is caused by carbon dust from the brushes being blown through the armature. High speed causes this dust to build up into a conductive layer inside the armature (you cant see it without a boroscope). In winter moisture from the air adds to the problem increasing its conductivity, eventually there is enough current to cause an arc. The arc destroys the enamel insulation and a fire starts inside the armature.
Liquid copper then shoots out and makes contact with the field winding which is NOT protected. The field winding supply is not isolated from the armature supply so damaging current can flow between the two circuits, this destroys both the motor and speed controller....

This is a post mortem video.

This view is of the flashover region.

The DVM shows low resistance to chassis.

Carbon dust coming from armature interior.

Brush Check at 58000 miles

Swap two brushes for copper graphite composition Commutator arcing has stopped 65MPH does not cause arcing Pure graphite brush wore out