# Help! Zilla problems



## EVDL List (Jul 27, 2007)

Hey Matt

Being you just had the motor worked on I doubt there
is a short to frame there. I've seen where assuming
gets you so taking a test of the motor is easy. Use a
multi-meter and see whether you have continuity
between any terminal from the housing. 

While you're there testing it, do a 12 volt bench test
to see that the motor does in fact work (if you didn't
already after getting it back from the shop) again
just to make sure so you can cross this segment off
the list so to speak.

Being that the motor's been worked on and the problem
remains it adds to it not being the issue but like I
said if you want to cross it off you'll at least know.


Bummer to hear you're having troubles, keep the chin
up and trace it till you find the little bugger 8^)

Sorry I can't help more on the controller but Otmar
wouldn't let me see the insides of one 8^o, LMAO!
(kind of a private / public joke) 8^P No diff really
as I couldn't tell ya what I saw if I saw it, being
I'm the motor guy 8^)

Hope this helps a little ><
Best of luck
Jim Husted
Hi-Torque Electric






> --- "R. Matt Milliron" <[email protected]> wrote:
> 
> >
> > I do not want to send My Zilla 1k-LV back to the
> ...


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## EVDL List (Jul 27, 2007)

Hello Matt,

If you connect directly to a main contactor, that may have a large inductive 
kick when the contactor is turn off. This is what my did and the hairball 
and it took out the driver circuit for the contactor.

It is recommended by Otmar of Café of Electric, to install a snubber across 
the main contactor coil. This diode is a Zener Overvoltage Transient 
Bidirectional type. I use a NTE-4933 or equal type.

The inductive kick in some contactors is too large for the hairball and can 
damage it.

I use both the NTE-4933 suppression on the contactor coil, plus I have the 
hairball contactor circuit, drive a small 12 volt relay that only draws 
about .1 amp and have this relay turn on the main contactor. I took off 
directly off the ignition key circuit, because my large contactor draws 
about 5 amps.

The 56 volt is not a short in the way you think. When the batteries are 
charge, they vent and these causes a conductive path from any one of the 
battery terminals to the chassis ground of the EV. After charging, you may 
read a voltage from one of battery terminals to ground. You can even read a 
conductive voltage from the post to the plastic case of the battery. This 
is normal for a venting battery.

Now when you have this conductive path from you battery pack to vehicle 
ground, the other path may be through your motor to ground. This current 
path is from the negative of the battery to the negative of the Zilla 
controller directly tie to the negative M- to the motor.

When a DC motor is ran for a period of time, there is brush dust that forms 
a conductive path from the brushes, down the face of the commentator and to 
the motor shaft and frame of the motor which also makes contact to the 
vehicle frame.

This is your conductive path, one battery feed line from the battery to 
frame and the other battery feed line that goes directly to the Zilla, to 
the motor and then to ground. This is your current circuit.

To current path is induce by a higher voltage when you batteries are 
charging. If this conductive path is not broken, more brush dust will 
increase this current path, and the voltage could get up to the full battery 
voltage.

When charging your batteries, it is best to disconnect both the positive and 
negative battery leads to your controller. I use two more contactors, which 
is the same size of the main contactor, which disconnects the batteries from 
the controller and motor when the ignition key is off. I use another small 
12 volt relay control by the ignition circuit to control these two battery 
contactors, which normally are call safety contactors.

Safety contactors are also control by a on dash or on console kill switch, 
just in case the main contactor or controller fails.

Also, if you have a on board battery charger, it is best to have a two pole 
50 to 75 amp contactor which is used to connected the battery charger to the 
batteries. If I leave my PFC-50 battery charger connected to the batteries 
at all time, the battery circuit will arc every time the battery circuit is 
disconnected some where in the circuit.

Always disconnect the battery charger from the batteries, which should be 
some distance from the batteries them selfs, if you disconnect a link off a 
battery. With my battery charger connected and even not plug in to the AC, 
the links will arc when I disconnected. This could blow up your batteries 
if you have battery fumes present.

A 2 pole battery contactor on the DC side of the battery charger will 
prevent this arcing, plus cut out another conductive ground path, if you 
battery charger is grounded to the vehicle.

I install my battery charger inside a epoxy coated fiberglass enclosure, the 
main battery pack in a epoxy coated fiberglass enclosure, plus two 
contactors to isolated from the controller and another set of contactors to 
isolated from the battery charger while the EV is running.

I now have only .1 to .7 volt conductive current path to ground now.

When installing a new DC motor that has brushes, I take a ohm reading of the 
motor terminals, (disconnected from the controller), to give me a reference 
of the conduction to ground. When motor is new it will read over 20 meg 
ohms from any one of the battery terminals to the motor frame. As time goes 
on, it is normal for this to get to 30 to 50 K ohms which is cause by the 
brush dust and its time to clean the motor.

When I did maintenance on the motor, which means breaking it down, clean it, 
replacing the brushes, megger the motor circuits, and had the commentator 
turn and all the windings re-enamel and a weak spot in one of the field 
windings repair, I also had the motor shop apply insulating enamel on the 
face of the commentator down to the motor shaft and on the motor shaft up to 
the bearing surfaces. Also I had them spray a insulating enamel you can 
also get in a spray can from the motor shop, which I use to spray all the 
inside metal surfaces of the motor after the field coils are install. The 
field coils shoes must have a metal to metal contact with the motor housing.

It is best to call or Email Otmar on your hairball. I had to send my back 
to him, he replace the driver circuit for the main contactor and got it back 
in about a week which he included some Zener Overvoltage Diodes to be 
install across the contactor coils. The controller has been working good for 
about 5 years now.

Roland


----- Original Message ----- 
From: "R. Matt Milliron" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 26, 2007 9:42 PM
Subject: Help! Zilla problems


>
> I do not want to send My Zilla 1k-LV back to the shop. I am hoping
> that the EV-Brain trust can help me.
>
> Short story. I got my Zilla. Hooked it up and it ran. Drove my
> car for 2 miles. Parked it, turned everything off. Started chargers
> and went to bed. Next day she won't run. Hairball will not talk to
> the power unit. Also there is a 56 volt short too ground/body of the
> car. I figured that it was the motor. Got the motor back from the
> shop, with a clean bill of health and a bill. Hooked it to the Zilla
> (1132 error) hairball will not talk to the power unit. I also have a
> 56 volt short to ground/body of car. If I disconnect Zilla (M+) from
> motor, short goes away. If I move the volt meter one battery farther
> from the Zilla, the short drops 6 volts. Is this something with the
> motor or Zilla? Is it something I can test for.
>
> My feeling is that this is just something that happens. Some
> component in the power unit, stressed itself and failed. I just don't
> want to be wrong.
>
> TIA
>
> R. M. Milliron
>
> [email protected]
> 1981 Jet Electrica
> http://www.austinev.org/evalbum/702
>
> This machine has been garaged for 17 years.
> I am upgrading it and getting it running. Tabitha,
> my daughter, named it, "Pikachu". It's yellow and black,
> electric and contains Japanese parts, so I went with it.
>
>


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## EVDL List (Jul 27, 2007)

> On 26 Jul 2007 at 23:56, Roland Wiench wrote:
> 
> > When a DC motor is [run] for a period of time, there is brush dust that forms a
> > conductive path from the brushes, down the face of the [commutator] and to the
> ...


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## EVDL List (Jul 27, 2007)

Flame On ;-P
A year and a month and that hasn't happened to me yet. I'm not saying it won't. But I wouldn't worry a new person about it being that big of a problem though. The capital cost difference was worth having to take the time once a year to take an air hose the to motor.

Mike

----- Original Message -----
From: David Roden <[email protected]>
Date: Friday, July 27, 2007 9:09 am
Subject: Re: Help! Zilla problems
To: [email protected]



> > On 26 Jul 2007 at 23:56, Roland Wiench wrote:
> >
> > > When a DC motor is [run] for a period of time, there is brush
> > dust that forms a
> ...


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## EVDL List (Jul 27, 2007)

Hey Jim,

I gotta say motors out of your shop look a whole lot
nicer than what the other guy did for Matt's MTC. Not
to say they didn't do a decent job, but you can tell
it is not the master's work.

And Matt,

About that 56 volt ground. Is that from battery pack
positive to frame? Try taking a 1K or 2.2K Ohm
resistor and wiring it from pos to frame and measure
the drop across the resistor. Does the voltage go
down from 56? Use I = V / R to calculate the amps. 
Milliamps, hopefully. If you're below 10 milliamps,
it is probably leakage paths from the batteries,
either tracking from terminals outside the cases or
even thru the plastic cases.

Jeff



> --- Jim Husted <[email protected]> wrote:
> 
> > Hey Matt
> >
> ...


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## EVDL List (Jul 27, 2007)

> --- Jeff Major <[email protected]> wrote:
> 
> >
> > Hey Jim,
> ...


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