Search found 103 matches

by bobc
Fri Jun 06, 2008 12:28 am
Forum: Cars,Vans and other road vehicles
Topic: AC motor/controller sources
Replies: 9
Views: 8965

PMS motor has a sinusoidal mmf distribution around the airgap whereas with brushless DC it's trapezoidal. In the inverter the PMS motor expects to be given sinewaves which are a wee bit trickier to make than the trapezoidal voltage for a BLDC. In the BLDC case it is usual to open circuit the "s...
by bobc
Wed Jun 04, 2008 10:36 pm
Forum: Cars,Vans and other road vehicles
Topic: AC motor/controller sources
Replies: 9
Views: 8965

Interesting links Malcolm - the last one in particular gives plenty of information & tries hard to "sell" the AC solution. I was interested to see that all the motor options were liquid cooled. I note that nobody seems to have used my system & gotten a standard industrial motor rew...
by bobc
Thu May 29, 2008 12:20 pm
Forum: Cars,Vans and other road vehicles
Topic: Regenerative Braking/Decelleration??
Replies: 6
Views: 6917

with AC traction, particularly induction motor, you inherently get regeneration.
by bobc
Thu May 29, 2008 12:17 pm
Forum: All things battery related
Topic: Nanosafe(TM) batteries
Replies: 1
Views: 2640

Nanosafe(TM) batteries

Anybody know anything about these "nanosafe" batteries - they sound good but probably exhorbitant....... http://www.altairnano.com/documents/NanoSafeBackgrounder060920.pdf http://www.lightningcarcompany.co.uk/ the car looks nice too - but they want a 15 grand deposit - you'd have to be bar...
by bobc
Tue May 20, 2008 12:08 pm
Forum: Cars,Vans and other road vehicles
Topic: Two- or three-speed gearbox?
Replies: 22
Views: 15526

Your efficiency figures for the motor look so good I wonder if you'll really need liquid cooling? the reason for liquid cooling is mainly so I can use the original heater matrix for demisting, also it should make the inverter design a bit easier. The motor efficiency figures neglect core losses and ...
by bobc
Tue May 20, 2008 9:21 am
Forum: Cars,Vans and other road vehicles
Topic: Two- or three-speed gearbox?
Replies: 22
Views: 15526

Peter,
you're squaring/cubing the power
no no no no no - it's the speed you have to square/cube (cube actually) to get the power ;^)
The 6x2x2x2 in my email above was because the speed has doubled.
bob
by bobc
Mon May 19, 2008 6:45 pm
Forum: Cars,Vans and other road vehicles
Topic: Two- or three-speed gearbox?
Replies: 22
Views: 15526

yeah Malcolm, it will be a liquid cooled mosfet inverter (both firsts for me....) (I do industrial IGBT inverters for my day job). My motor is a standard 5.5kW TEFC induction motor, I had it rewound by ASK rewinds in Altham to 70V - that cost me £250. I'm converting the motor to liquid cooling by...
by bobc
Mon May 19, 2008 11:45 am
Forum: Cars,Vans and other road vehicles
Topic: Two- or three-speed gearbox?
Replies: 22
Views: 15526

Hyve - your power/speed maths seems a little muddled - might be just "finger trouble" - 1) drag is a force. & drag is proportional to speed squared. 2) power = force x speed so power is proportional to speed CUBED. so in your example, neglecting friction losses, if 6kw is needed for 35...
by bobc
Fri May 02, 2008 12:36 pm
Forum: Hot off the press....
Topic: BVS at the Green Power Corporate Challenge
Replies: 21
Views: 13811

The average speed of the winning car at the weekend was just over 30mph. That includes mandatory pitstops and battery/driver changes. The winning car has averaged 32mph over the 4 hrs. The old streamliner distances only look impressive because they used to be 6 hour races - in fact the record distan...
by bobc
Thu May 01, 2008 9:59 am
Forum: Home Energy Area
Topic: Is this the holy grail......?
Replies: 1
Views: 13531

Is this the holy grail......?

New solar PV technology - claim cost down to 1% silicon and efficiency up to 25%
I wonder when we'll be able to buy these....

http://www.eetimes.eu/207403402

Bob

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