# [EVDL] Rectification - What's wrong?



## EVDL List (Jul 27, 2007)

I'm trying to test the motor controller I just bought (Curtis
1204-412). I don't have my batteries yet. So, I've rigged a system
like the typical BadBoy. But it's not working how I would expect.

I have a variac (autotransformer) set to give me 48 VAC. I verified
this with my cheapo multimeter. I got a cheap rectifier from
RadioShack [1] that's rated 50 V and 25 amp. (That should be enough
for low-power/no-load testing, right?) So, I soldered the 48 VAC to
two pins of the bridge rectifier that have the wave label. Then I
soldered another two wires to the + and - terminals. I assumed the
wave pins were for the AC and it didn't matter which wire went to
which terminal. And the + and - terminals were the DC. Is that
right?

So, I switched my cheapo multimeter to DC and measured the output of
the rectifier. It's 62.9 VDC. Always. Doesn't matter if I turn the
variac down to 20 or less VAC. The multimeter still reads 62.9 VDC
out of the rectifier. Is my multimeter just dumb and reporting the
frequency (62.9 is pretty close to the 60 Hz of the AC power)? Or is
there something wrong with my circuit?

Thanks,
Steven

References:
[1] http://www.radioshack.com/product/index.jsp?productId=2062584

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

> SteveS <[email protected]> wrote:
> > First off - I hope you understand that an autotransformer does not
> > isolate you from the AC line? That's a really dangerous way to experiment!
> 
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

Replies below:

Steven ** wrote:
>


> SteveS <[email protected]> wrote:
> >
> >> First off - I hope you understand that an autotransformer does not
> >> isolate you from the AC line? That's a really dangerous way to experiment!
> ...


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## EVDL List (Jul 27, 2007)

On Thu, Apr 10, 2008 at 10:05 AM, Steven **
<[email protected]> wrote:

>
> Why is a rectifier rated at 50PIV not enough for 48VAC? I

The peak voltage of an AC (assuming sinusoidal) waveform is square
root of three times the RMS voltage -- so the peak voltage of 48VAC
RMS is about 83 volts.


> I don't have 12V batteries right
> now. Hence the need for the setup.

Actually, you probably do.... in your ICE (if you have one of them,
that is). That's how I've been testing my motors (though, probably
not controllers).... set of #4AWG jumper cables from the car battery,
with the engine running, seems to handle 300 amp draws at 12 volts
quite nicely for short duration testing.

Z

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## EVDL List (Jul 27, 2007)

> ---- The meter is reading the RMS voltage. For a sine wave the PEAK
> voltage is 1.4 * that or 67 volts. Your rectifier is 50PIV - PEAK
> inverse volts. Theoretically it could blow, though they have some safety
> factor. In general, you should use overrated components, which is why I
> suggest 100PIV.\



Ooops. You are right. Peak is sqrt(2) times RMS, not sqrt(3) times,
as I said in my earlier email. Getting confused with my three phase
power :-<

Z

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## EVDL List (Jul 27, 2007)

That'd be one 12V battery. Doesn't really get me to 48 or even 36
V... I've already tested the motor that way. But I need at least 36V
to test the controller.

-Steven



> Zeke Yewdall <[email protected]> wrote:
> > On Thu, Apr 10, 2008 at 10:05 AM, Steven **
> > <[email protected]> wrote:
> > > I don't have 12V batteries right
> ...


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## EVDL List (Jul 27, 2007)

Do you have more than one ICE? You could get a whole bunch of jumper
cables and chain them together in series to get higher voltage....
that sounds really dangerous though. I wouldn't recommend it.

If you aren't ready to buy the main traction pack yet, you could buy
some cheap starter batteries -- maybe get some for $35 each, to just
do some quick testing. Then, you could use at least one of them as
the Auxiliary battery later.

Z

On Thu, Apr 10, 2008 at 11:48 AM, Steven **
<[email protected]> wrote:
> That'd be one 12V battery. Doesn't really get me to 48 or even 36
> V... I've already tested the motor that way. But I need at least 36V
> to test the controller.
>
> -Steven
>
>
>


> Zeke Yewdall <[email protected]> wrote:
> > > On Thu, Apr 10, 2008 at 10:05 AM, Steven **
> > > <[email protected]> wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

I had this thought. It just seems like such a waste to buy 4
batteries that I would never use again. Especially if it costs me
$140 (which is $40 more than the controller cost).

And no. I only have one ICE, my Prius. I had thought about trying to
convince some friends to bring their cars over and borrow their
batteries for a day. But pulling the power from the grid seemed like
a much more elegant and useful solution.

-Steven



> Zeke Yewdall <[email protected]> wrote:
> > Do you have more than one ICE? You could get a whole bunch of jumper
> > cables and chain them together in series to get higher voltage....
> > that sounds really dangerous though. I wouldn't recommend it.
> ...


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## EVDL List (Jul 27, 2007)

Guys,
Let's back up a little. I was a marine installer some eons ago and have
brought all of those practices forward with me. Why are you testing your
controller? Unless you are doing comparison testing or maybe spec testing
for a magazine or the like, what's the purpose except to waste your time and
possible ruin the unit with your kluging fir the setup and then what? Try to
return it as faulty? I wouldn't waste my time. Continue with the project, do
it right. The results will show and give you he grin when the time is right.


You are taking too many chances for all the wrong reasons,

Mark Grasser



-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Steven **
Sent: Thursday, April 10, 2008 1:49 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Rectification - What's wrong?

That'd be one 12V battery. Doesn't really get me to 48 or even 36
V... I've already tested the motor that way. But I need at least 36V
to test the controller.

-Steven



> Zeke Yewdall <[email protected]> wrote:
> > On Thu, Apr 10, 2008 at 10:05 AM, Steven **
> > <[email protected]> wrote:
> > > I don't have 12V batteries right
> ...


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## EVDL List (Jul 27, 2007)

Replies inline.

-Steven



> SteveS <[email protected]> wrote:
> > Replies below:
> >
> >
> ...


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## EVDL List (Jul 27, 2007)

Uh... To verify that it works, maybe? Cause I got it on eBay and
have a very limited return window. If I wait till it's ready to go in
the car (which is months off), there is zero chance they'd give me a
refund at that point.

I'm going to ignore the insulting tone of the rest of your response.

-Steven



> Mark Grasser <[email protected]> wrote:
> > Guys,
> > Let's back up a little. I was a marine installer some eons ago and have
> > brought all of those practices forward with me. Why are you testing your
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

> EVDL Administrator <[email protected]> wrote:
> > On 10 Apr 2008 at 11:05, Steven ** wrote:
> > > The 48 VAC was measured with the multimeter set to VAC. I would
> > > assume that meant it's RMS. But I don't know. It was cheap when I
> ...


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## EVDL List (Jul 27, 2007)

Just FYI,
It's an email, I never write in an insulting tone. You are doing scary
dangerous things though, as others have mentioned.
In other words, I'm with them. Even used batteries from the local service
station would be a better idea then what you have been trying.

Sorry that I write in such a way as to offend,

Mark Grasser

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Steven **
Sent: Thursday, April 10, 2008 3:04 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Rectification - What's wrong?

Uh... To verify that it works, maybe? Cause I got it on eBay and
have a very limited return window. If I wait till it's ready to go in
the car (which is months off), there is zero chance they'd give me a
refund at that point.

I'm going to ignore the insulting tone of the rest of your response.

-Steven

On Thu, Apr 10, 2008 at 1:00 PM, Mark Grasser <[email protected]>


> wrote:
> > Guys,
> > Let's back up a little. I was a marine installer some eons ago and have
> > brought all of those practices forward with me. Why are you testing your
> ...


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## EVDL List (Jul 27, 2007)

> Steven wrote:
> 
> > Uh... To verify that it works, maybe? Cause I got it on
> > eBay and have a very limited return window. If I wait till
> ...


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## EVDL List (Jul 27, 2007)

> On 10 Apr 2008 at 11:59, Zeke Yewdall wrote:
> 
> > If you aren't ready to buy the main traction pack yet, you could buy
> > some cheap starter batteries -- maybe get some for $35 each, to just
> ...


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## EVDL List (Jul 27, 2007)

> Uh... To verify that it works, maybe? Cause I got it on eBay and
> have a very limited return window. If I wait till it's ready to go in
> the car (which is months off), there is zero chance they'd give me a
> refund at that point.

Are you positive that the seller isn't on this list? I know that if /I/
was the seller I wouldn't refund your money at this point. Given that /I/
wouldn't sell it without first testing it and the high probabibility that
your testing caused the damage (if the controller is damaged)

Seriously, if you hook everything up and it doesn't work, how do you know
whether it was already broken or whether you toasted it?

Another option for testing it occures to me, you could take it into a
golfcart dealer/repair shop and have them bench test it for you. If you
tell them what it's for they might do it for free.

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Steven ** wrote:
> > > I actually think it might be RMS since the reading of the
> ...


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## EVDL List (Jul 27, 2007)

Yeah, your meter is probably reading correctly. Usually the 'averaging' 
types are set up to show RMS when the input is sinusoidal. It's when you 
are trying to measure something with an odd waveform that cheap meters 
get it wrong. The markings are RMS.

- SteveS

Steven ** wrote:
>


> EVDL Administrator <[email protected]> wrote:
> >
> >> On 10 Apr 2008 at 11:05, Steven ** wrote:
> >> > The 48 VAC was measured with the multimeter set to VAC. I would
> ...


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## EVDL List (Jul 27, 2007)

Thanks for the info. I will attempt to implement your suggestions in
the future.

But for now, I'm satisfied the controller is working. The setup
several people were convinced would kill me or my controller did
neither. The motor spins up and down depending on my potentiometer
setting. It doesn't spin very fast, but I don't think that indicates
any problems.

I think the trick was re-wiring the motor per the Curtis 1231 diagram
(the 1204's diagram had extra stuff for reversing the motor that
confused me) which differed--at least in my interpretation--from the
instructions on the motor.

-Steven



> Roger Stockton <[email protected]> wrote:
> > Steven wrote:
> >
> > > Uh... To verify that it works, maybe? Cause I got it on
> ...


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## EVDL List (Jul 27, 2007)

Glad it's working. Sorry if we went overboard on the variac. I find 
accidents happen when two or more things go wrong at the same time. A 
variac removes one safeguard so the chance for trouble goes up. It isn't 
deadly by itself. Good luck with it!

- SteveS

Steven ** wrote:
> Thanks for the info. I will attempt to implement your suggestions in
> the future.
>
> But for now, I'm satisfied the controller is working. The setup
> several people were convinced would kill me or my controller did
> neither. The motor spins up and down depending on my potentiometer
> setting. It doesn't spin very fast, but I don't think that indicates
> any problems.
>
> I think the trick was re-wiring the motor per the Curtis 1231 diagram
> (the 1204's diagram had extra stuff for reversing the motor that
> confused me) which differed--at least in my interpretation--from the
> instructions on the motor.
>
> -Steven
>
>


> Roger Stockton <[email protected]> wrote:
> >
> >> Steven wrote:
> >>
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

Hi, I'm glad to hear your tests were successful.
If you are in the Seattle area and need them for any reason I have
two 12v starter batteries you can borrow, but I'd like to be there to
learn from you if you use them.
Hope all your projects turn out well.

On Thu, Apr 10, 2008 at 6:26 PM, Steven **
<[email protected]> wrote:
> Thanks for the info. I will attempt to implement your suggestions in
> the future.
>
> But for now, I'm satisfied the controller is working. The setup
> several people were convinced would kill me or my controller did
> neither. The motor spins up and down depending on my potentiometer
> setting. It doesn't spin very fast, but I don't think that indicates
> any problems.
>
> I think the trick was re-wiring the motor per the Curtis 1231 diagram
> (the 1204's diagram had extra stuff for reversing the motor that
> confused me) which differed--at least in my interpretation--from the
> instructions on the motor.
>
> -Steven
>
>
>
>


> Roger Stockton <[email protected]> wrote:
> > > Steven wrote:
> > >
> > > > Uh... To verify that it works, maybe? Cause I got it on
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

What are these sources for rectifiers?

The reason I didn't have an isolation transformer or high spec parts
is because I was just using what I could get my hands on with short
notice. Everything I used was either borrowed or bought from the
local RadioShack. I had 7 days to report any issues with the
controller before I'd be left holding the bag. I ran my setup for
maybe 30 seconds, which is probably why I didn't have anything fail
from running so close to their max spec.

If I use this setup again in the future, I'll have the time to order
better parts and make it a proper setup.

-Steven



> Lee Hart <[email protected]> wrote:
> > Steven ** wrote:
> > > I was looking into borrowing an osciliscope to test. How can I
> > > isolate it to avoid damage?
> ...


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## EVDL List (Jul 27, 2007)

When I was a kid Radio shack was great, but they've really gone
towards the consumer electronics instead of electronic components
nowadays. Still good for a quick part, but hard to put together some
of the more custom circuits.

JB Saunders (if you are in Boulder), Jameco (online), Marlin P Jones
(on line), an Herbach and Rademan (on line) are the ones that I end up
using alot. There are also major electronics suppliers like Allied
Electronics and Digikey -- not sure if they sell to the public, or
only business to business.

Z

On Fri, Apr 11, 2008 at 10:22 AM, Steven **
<[email protected]> wrote:
> What are these sources for rectifiers?
>
> The reason I didn't have an isolation transformer or high spec parts
> is because I was just using what I could get my hands on with short
> notice. Everything I used was either borrowed or bought from the
> local RadioShack. I had 7 days to report any issues with the
> controller before I'd be left holding the bag. I ran my setup for
> maybe 30 seconds, which is probably why I didn't have anything fail
> from running so close to their max spec.
>
> If I use this setup again in the future, I'll have the time to order
> better parts and make it a proper setup.
>
> -Steven
>
>
>
>


> Lee Hart <[email protected]> wrote:
> > > Steven ** wrote:
> > > > I was looking into borrowing an osciliscope to test. How can I
> > > > isolate it to avoid damage?
> ...


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## EVDL List (Jul 27, 2007)

> Zeke Yewdall wrote:
> 
> > There are also major electronics suppliers like Allied
> > Electronics and Digikey -- not sure if they sell to the
> ...


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## EVDL List (Jul 27, 2007)

> Zeke Yewdall wrote:
> > When I was a kid Radio shack was great, but they've really gone
> > towards the consumer electronics instead of electronic components
> > nowadays. Still good for a quick part, but hard to put together some
> ...


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## EVDL List (Jul 27, 2007)

I usually use Digikey; they have a huge selection, decent prices, and
very fast shipping.

However, for electromechanical stuff (switches, potentiometer knobs,
wire ducts), I've found that Mouser often has a better selection.

-Morgan LaMoore



> Zeke Yewdall <[email protected]> wrote:
> > When I was a kid Radio shack was great, but they've really gone
> > towards the consumer electronics instead of electronic components
> > nowadays. Still good for a quick part, but hard to put together some
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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