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[evtricity]

In the video at you can hear the cutout. It occurs 10 seconds in. It's only momentary and the power comes back on.

Hope this helps explain the cutout.

[GambitDash]

Not to be confused with the metallic noise/vibration of the SR under hard acceleration.

Is this the same noise I would hear heading up a very steep hill under acceleration?


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[evtricity]

Probably. Listen to the video I just posted right from the start of the race and you will hear the sound of the SR motor under full acceleration.

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[GambitDash]

Well heck, that doesn't sound anything like anything I've ever heard of before

I've got a phone mount, I should try recording it.  Was that inside your windshield?

[evtricity]

Yes, behind the windscreen. There is also a loud white noise even before the bike leaves the start line. That is the electric ducted fan that forces air through the motor for cooling.

[Lipo423]

The best is when you overtook the rider ahead of you 2'45" 
He's got a damn powerful bike 

[RNM]

Volts from controller - volts from back EMF = working voltage.

At low RPM the voltage from the controller is high and volts from back EMF is low so you have lots of working voltage.  As RPM increases the working voltage approaches zero.

Zero working voltage = zero torque

Basically, the harder you push the more it pushes back. But field weakening limits the amount it pushes back.

Field weakening basically allows you to keep positive working voltage at high RPM.  Field weakening can be applied to SPM motors but requires LOTS of current and you need to have a better cooling solution because of the amount of heat generated.

IPM motors are perfect candidates for field weakening and it can be done at the power levels required at lower RPM.  As a result IPM motors can hit much higher RPM without additional cooling required

Great info Mrwilsn, thanks!

Can you point to some books and/or papers online about field weakning?

IPM = internal mounted PM rotor and SPM = surface mounted PM rotor?

[dean mcneil]

I would like to modify the torque settings as described,  can they be modified using a sevcon hand held calibrator or do you need the pc  program? Ive been trying to rent the hand held from Thunderstruck, but the last person to borrow it, will not return it. Therefore I would need to buy one at $450,ugh. What is the best way to go. Ive got a dongle but without the passwords it doesnt go far.

[evtricity]

What dongle do you have?

[dean mcneil]

Purchased Dongle from Hollywood Electric.

[evtricity]

Purchased Dongle from Hollywood Electric.

I believe that the dongles only allows you to access the Main Bike Board (MBB). You need an IXXAT USB to CAN adaptor and Sevcon PC software to change torque curves on the Sevcon controller on a Zero.

[dean mcneil]

Will the sevcon handheld calibrator work?

[dean mcneil]

The handheld calibrator plugs directly into the controller or the obd2 port. Im not sure what the capabilities are, it note that it is "suitable for fine tuning an existing setup"   whatever that means.

[evtricity]

I'm not aware of anyone using that device to configure a Zero's torque curve. Perhaps it could be used to upload/flash a Sevcon configuration file however the Zero OBD port uses an uncommon pin format which I doubt this hand-held unit would work with.

[dean mcneil]

is the controller running off is own program or is it running off zeros?