hall effect throttle question

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hall effect throttle question

fred ungewitter
Good day, denizens of the EVDL. As a long time owner of Gizmo EV number 30, I've gained great benefit from the combined wisdom of the list members and I'm hopeful to make use of your talents again.

I recently suffered a controller fault and replaced my Sevcon Powerpak SEM with a spare, slipping out the undamaged logic board and placing it into a healthy MOSFET assembly. The silence of the contactor was replaced with the familiar clunk on key-twist, but all is not well.

My Sevcon calibrator now reads a throttle fault, a potentiometer error by LED flash count. The calibrator also showed a failure of the FS1 safety circuit, easily bypassed with a jumper wire, but the throttle fault remains. The calibrator shows zero percent when moving the throttle, while it should read from zero to one hundred percent when functioning properly. I've performed this check in the past and found it to be so, even when not moving.

The Gizmo of this era uses a custom-made circuit, commonly called Norm, although I believe there is no relationship to a bar in Boston, MA, USA. This circuit checks the various parameters such as throttle off, seat safety switch, brake switch and directional switch, among other unknown things. Due to operator error in the past, the 12v wiring on which this device operates was joined with the approximately 66v of the pack. Part of the circuit became inoperative, necessitating a manual FS1 switch, which is now no longer functioning, but very little else went awry.

With this recent failure, the throttle appears to be non-communicative. I understand that it's a Hall-Effect throttle and earlier disassembly bears this out. There are two magnets on either end of the arc of travel and something in the middle, or there's a magnet in the middle and two somethings at either end. My controller is likely configured by pin connection for a 0-5v input, although it will accept a resistive input asĀ  well. I'd prefer to keep the existing throttle, as it is the trigger of an F-16 style joystick grip on the steering handle and quite convenient.

I am of the mind that hall effect throttles are not particulary uncommon and perhaps do not require sophisticated custom circuitry constructed by someone named Norm. Because I can access the three leads (or however many there are) at the end of the steering grip, I can connect my throttle in an approved manner to the controller, which is as easily accessed at the rear of the vehicle. It's the part in the middle that has me concerned.

The controller provides 5ma at 12v, ostensibly for such a purpose and I can pull 12v from the converter as needed if 5ma is insufficient. What is in between the throttle mechanism of a hall-effect throttle and the controller? Is this a somewhat-standard EV part, or do I need to approach it from the Arduino level and build my own conversion thingy?

I've read plenty of references here in the list to curtis throttle pots, but almost nothing regarding hall effect. Where is the best place to find the necessary device or to learn to build one?

thanks

fred
daytona beach, fl
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Re: hall effect throttle question

David Nelson-5
Hi Fred,

I posted a response to your post at
http://levforum.com/forum/index.php?topic=24.0 but I thought I'd post
here too for completeness.

The Hall-Effect in the Gizmo uses a 5V source not 12V. The Norm
circuit converts the 12V to the 5V needed along with the FS1 switching
and delaying the throttle voltage coming up while the controller
boots. In the design of the Black Sheep Technology
(http://black-sheep.us/) replacement a startup delay had to be
programmed in to give the controller time to boot up so it wouldn't
give a Throttle pot fault. I posted the schematic of the original Norm
circuit along with the assembly code it ran in the LEVforum thread.

Given the design of the handles on our particular Gizmos it would take
a total handle replacement to go with a pot instead of the
Hall-Effect. While you could build a direct replacement of the Norm
circuit you might want to consider the upgrade to what I'm using.
Variable regen is really nice and definitely makes the Gizmo stop much
faster when necessary.



On Sat, Aug 25, 2012 at 4:35 PM, fred <[hidden email]> wrote:

> Good day, denizens of the EVDL. As a long time owner of Gizmo EV number 30, I've gained great benefit from the combined wisdom of the list members and I'm hopeful to make use of your talents again.
>
> I recently suffered a controller fault and replaced my Sevcon Powerpak SEM with a spare, slipping out the undamaged logic board and placing it into a healthy MOSFET assembly. The silence of the contactor was replaced with the familiar clunk on key-twist, but all is not well.
>
> My Sevcon calibrator now reads a throttle fault, a potentiometer error by LED flash count. The calibrator also showed a failure of the FS1 safety circuit, easily bypassed with a jumper wire, but the throttle fault remains. The calibrator shows zero percent when moving the throttle, while it should read from zero to one hundred percent when functioning properly. I've performed this check in the past and found it to be so, even when not moving.
>
> The Gizmo of this era uses a custom-made circuit, commonly called Norm, although I believe there is no relationship to a bar in Boston, MA, USA. This circuit checks the various parameters such as throttle off, seat safety switch, brake switch and directional switch, among other unknown things. Due to operator error in the past, the 12v wiring on which this device operates was joined with the approximately 66v of the pack. Part of the circuit became inoperative, necessitating a manual FS1 switch, which is now no longer functioning, but very little else went awry.
>
> With this recent failure, the throttle appears to be non-communicative. I understand that it's a Hall-Effect throttle and earlier disassembly bears this out. There are two magnets on either end of the arc of travel and something in the middle, or there's a magnet in the middle and two somethings at either end. My controller is likely configured by pin connection for a 0-5v input, although it will accept a resistive input as  well. I'd prefer to keep the existing throttle, as it is the trigger of an F-16 style joystick grip on the steering handle and quite convenient.
>
> I am of the mind that hall effect throttles are not particulary uncommon and perhaps do not require sophisticated custom circuitry constructed by someone named Norm. Because I can access the three leads (or however many there are) at the end of the steering grip, I can connect my throttle in an approved manner to the controller, which is as easily accessed at the rear of the vehicle. It's the part in the middle that has me concerned.
>
> The controller provides 5ma at 12v, ostensibly for such a purpose and I can pull 12v from the converter as needed if 5ma is insufficient. What is in between the throttle mechanism of a hall-effect throttle and the controller? Is this a somewhat-standard EV part, or do I need to approach it from the Arduino level and build my own conversion thingy?
>
> I've read plenty of references here in the list to curtis throttle pots, but almost nothing regarding hall effect. Where is the best place to find the necessary device or to learn to build one?
>
> thanks
>
> fred
> daytona beach, fl
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> | Please take those discussions elsewhere.  Thanks.
> |
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--
David D. Nelson
http://evalbum.com/1328
http://2003gizmo.blogspot.com
http://www.levforum.com

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| Moratorium on drag racing discussion is in effect.
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