Search found 103 matches

by bobc
Thu May 28, 2009 7:46 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

Just got my motor turning with the external optos - always a good moment! I was supplying it with 1amp, current controlled, & this is an 80A motor, plus I think I only had 2.5 phases working right... but it should all be downhill now. My drive PCB is a single sided board made by a mate (in his k...
by bobc
Tue May 26, 2009 8:55 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

Thanks Jeremy, BTW, I suspect that switching from delta to star might slip a 30degree(electrical not mechanical) factor into the mmf which might make it difficult to get best performance with a fixed sensor position, any thoughts? I guess 30degrees electrical doesn't amount to a great deal & wil...
by bobc
Mon May 25, 2009 10:45 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

Hi Jeremy,
can you tell me which bits you used for the hall sensors? save me doing the online catalog sweep....
The opto solution is proving to be a bit of a pain as I can't work on it in the shed when the sun's shining.........
thanks
Bob
by bobc
Tue May 19, 2009 4:56 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

Hi Jeremy, some good information there: I used an external slotted opto solution for feedback, I suspected the low speed running would be better with feedback. The fact that the motor is wired in delta is interesting; I may well fish out all 6 wires & wire the motors on a common shaft in series:...
by bobc
Mon May 18, 2009 7:47 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

A little bit more progress; parts of the circuit are coming to life, the logic works OK but the gate drivers don't yet. I've been putting the motor hardware together, here's a snap of the home made 'taperlok' thingy I'm using to connect the motors to the shaft http://i543.photobucket.com/albums/gg47...
by bobc
Thu May 14, 2009 6:46 pm
Forum: General
Topic: Greenpower racing at Gooodwood
Replies: 7
Views: 6023

Marktime, I think that was the Renishaw entry - nice car (but a bit big) with an orange nose. The Sandbach team had a bit of a 'mare with all cars having faulty throttle pots - must have got some damp in. Zebedee also had a grand total of 5 punctures on one wheel - we had to give up before the end, ...
by bobc
Wed Feb 04, 2009 11:02 pm
Forum: All things battery related
Topic: Lead acid battery temperature tests
Replies: 9
Views: 6945

OK energy needed to keep batteries hot is zero if they're well insulated! But keeping them permanently hot apparently increases self discharge & reduces life. But we are talking about a 50% increase in range, so not insignificant! As I suggested above, the peukert effect gives a very appealing e...
by bobc
Wed Feb 04, 2009 12:30 am
Forum: All things battery related
Topic: Lead acid battery temperature tests
Replies: 9
Views: 6945

Yes all quite unsuitable - 2hr discharge - lead acid car battery, deep discharge - none choices you would make if they weren't mandated by the "rules of the formula".... Anyway - I was expecting the hot results to give more volts out, due to reduced equivalent series resistance but was sho...
by bobc
Tue Feb 03, 2009 12:59 pm
Forum: All things battery related
Topic: Lead acid battery temperature tests
Replies: 9
Views: 6945

Lead acid battery temperature tests

Having failed to find credible data on this subject I have conducted some discharge tests at the 2hr rate. If I look at total energy supplied by a battery while being discharged to 9.9V (23C) or 9.5V(50C) I get the forllowing general results: charge and discharge cold - call this 100% charging at 50...
by bobc
Sun Jan 25, 2009 5:44 pm
Forum: General
Topic: 10kW BLDC outrunner drive
Replies: 18
Views: 20312

Not much progress lateley - been sourcing other bits & designing suspension. Anyway here are a couple of pictures... No. 1 is the first inverter made from toggle switches - confirmed the motor basically does what I thought & reached a maximum speed of about 0.1rpm http://i543.photobucket.com...

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