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Discussion Starter #1
Good day all. I appear to have been afflicted with a controller failure. It's a
Sevcon PowerPak SEM PP745 (48v, 500a) connected to a sepex motor and for the
last many thousands of miles has been working just great.

Recently, I discovered that I no longer had reverse. All switches check out
fine, all continuity is continuous, or something like that. I have the Sevcon
calibrator and no error messages appear on the display, although that's
inconclusive, as I may not be qualified to make that statement, nor to operate
it in such a manner as to validate the statement. The calibrator does confirm
that the controller is seeing the commands to go forward or reverse and
recognizes throttle position and that all safety protocols are safe.

When in reverse, with the drive wheel on a stand, the wheel jitters a bit and
may even move forward slightly. If I hand-start the wheel, it may rotate a few
times. Forward selection means the wheel turns normally, although on the road,
forward appears to be drawing more power than usual. My CycleAnalyst shows an
average of 100-120 watt hours per mil during a typical trip. The last trip was
about 160 watt hours per mile. That would be mildly alarming, but combined with
the lack of powered reverse, it's more so.

I've spoken to a number of electric motor/controller people and the general
consensus is that the controller has failed, although one consultant suggests
that the motor could have been damaged by the controller, or that the controller
could have damaged the motor. I've not checked visually for burned brushes or
bad spots on the commutator, but when I was turning the wheel by hand, the
action was quite smooth. When running slowly on the stand, the action was also
quite smooth (in forward). I took great care to keep the speed at a walking pace
or less, while there was no load applied to the system by having it in the air.

I have learned from one vendor that the Sevcon controllers may have a two month
lag time or greater. I contacted another vendor to see about getting my
controller repaired and was told to go through a retail level service location.
The one local contact appears on google maps to be a private residence, while I
was expecting a forklift repair location. The other two vendors are many miles
out of local range, but I may have to contact them to keep my options open.

Does anyone have any observations about the likelihood that it's the controller
and not the motor? Does anyone have any recommendations for a vendor who can
assess the controller and/or repair it? I think that since the local contact is
unlikely, any other contact is going to require shipping and I'm okay with that,
it means the whole country should come into consideration for my scope of
repair.

Also, if anyone has an NOS Sevcon PowerPak SEM 48v, 500a controller they want to
sell, please let me know.

thanks, your advice is greatly appreciated

fred




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Discussion Starter #2
Fred,

In addition to Jeff's suggestion you can use the calibrator to see
what voltage and current is going through the field and armature. I
can look up the menu number if you can't find it.

Also, you posted on the gizmo group that you were considering the
higher voltage PP784 controller as a replacement if needed. Section 5
of the manual shows that the voltage rang of the PP745 is 14.5-75V and
for the PP784 is 43.0-100V. Given that the PP745 won't pull in the
contactor above 70V, my guess is that the PP784 won't pull in the
contactor above 95V. FWIW, I have not yet seen below 56-57V under a
1.5C load with my 2P20S LFP at 87% DOD.


Jeff Major <[email protected]> wrote:
> Hi fred,
>
> For starters I'd switch the field wires, F1 and F2, and see if the motor =
then runs the opposite direction. If the problem follows and reverse on =
the controller still cogs even when that is actually forward on the motor, =
then I think we can conclude it is a controller problem.
>
> I may have a lead on a Sevcon 400 amp version, NOS.
>
> Regards,
>
> Jeff M
>
>
>
> --- On Wed, 9/15/10, fred <[email protected]> wrote:
>> Good day all. I appear to have been
>> afflicted with a controller failure. It's a
>> Sevcon PowerPak SEM PP745 (48v, 500a) connected to a sepex
>> motor and for the
>> last many thousands of miles has been working just great.
>>
>> Recently, I discovered that I no longer had reverse. All
>> switches check out
>> fine, all continuity is continuous, or something like that.
>> I have the Sevcon
>> calibrator and no error messages appear on the display,
>> although that's
>> inconclusive, as I may not be qualified to make that
>> statement, nor to operate
>> it in such a manner as to validate the statement. The
>> calibrator does confirm
>> that the controller is seeing the commands to go forward or
>> reverse and
>> recognizes throttle position and that all safety protocols
>> are safe.
>>
>> When in reverse, with the drive wheel on a stand, the wheel
>> jitters a bit and
>> may even move forward slightly. If I hand-start the wheel,
>> it may rotate a few
>> times. Forward selection means the wheel turns normally,
>> although on the road,
>> forward appears to be drawing more power than usual. My
>> CycleAnalyst shows an
>> average of 100-120 watt hours per mil during a typical
>> trip. The last trip was
>> about 160 watt hours per mile. That would be mildly
>> alarming, but combined with
>> the lack of powered reverse, it's more so.
>>
>> I've spoken to a number of electric motor/controller people
>> and the general
>> consensus is that the controller has failed, although one
>> consultant suggests
>> that the motor could have been damaged by the controller,
>> or that the controller
>> could have damaged the motor. I've not checked visually for
>> burned brushes or
>> bad spots on the commutator, but when I was turning the
>> wheel by hand, the
>> action was quite smooth. When running slowly on the stand,
>> the action was also
>> quite smooth (in forward). I took great care to keep the
>> speed at a walking pace
>> or less, while there was no load applied to the system by
>> having it in the air.
>>
>> I have learned from one vendor that the Sevcon controllers
>> may have a two month
>> lag time or greater. I contacted another vendor to see
>> about getting my
>> controller repaired and was told to go through a retail
>> level service location.
>> The one local contact appears on google maps to be a
>> private residence, while I
>> was expecting a forklift repair location. The other two
>> vendors are many miles
>> out of local range, but I may have to contact them to keep
>> my options open.
>>
>> Does anyone have any observations about the likelihood that
>> it's the controller
>> and not the motor? Does anyone have any recommendations for
>> a vendor who can
>> assess the controller and/or repair it? I think that since
>> the local contact is
>> unlikely, any other contact is going to require shipping
>> and I'm okay with that,
>> it means the whole country should come into consideration
>> for my scope of
>> repair.
>>
>> Also, if anyone has an NOS Sevcon PowerPak SEM 48v, 500a
>> controller they want to
>> sell, please let me know.
>>
>> thanks, your advice is greatly appreciated
>>
>> fred
>>
>>
>>
>>
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>
>
>
>
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>



-- =

David D. Nelson
http://evalbum.com/1328

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Discussion Starter #3
Jeff, I'm pretty happy to hear that you may have a Sevcon controller and the 400
amp version will work fine. I think the most I've ever pulled with this vehicle
is 300 amps and that was once, a transient spike. I appreciate very much the
troubleshooting suggestion, especially since it's a pretty easy thing to do, as
my controller is mounted out in the open. Please let me know what you find about
the NOS controller. Since David Nelson has provided some voltage range
information for the controller I have, as being within a range as high as 75v, I
probably will not go with the 80v version. It means I can increase the voltage
of my pack in the future without having to replace the controller that replaces
this damaged one. That's good news too.

David, I'm not sure what I'd be looking for and once I found it (in the
calibrator) what it would mean. Joe from Sevcon said if I tried to run in
reverse too much, I'd burn out the field coils, so I'm thinking that if the
controller is at fault, it's pumping huge currents where there should be none.
I did notice that the CycleAnalyst had the ammeter portion ripping along when I
selected reverse, so I stopped that pretty quickly.

I might get to swap the field connections today and see where it goes from
there.

thanks very much. This list is incredible as a resource for all of us.

fred


------------------------------

Original Message: 8
From: Jeff Major <[email protected]>
Subject: Re: [EVDL] Controller woes

Hi fred,

For starters I'd switch the field wires, F1 and F2, and see if the motor then
runs the opposite direction. If the problem follows and reverse on the
controller still cogs even when that is actually forward on the motor, then I
think we can conclude it is a controller problem.

I may have a lead on a Sevcon 400 amp version, NOS.

Regards,

Jeff M

------------------------------

Original Message: 12
From: David Nelson <[email protected]>
Subject: Re: [EVDL] Controller woes

Fred,

In addition to Jeff's suggestion you can use the calibrator to see
what voltage and current is going through the field and armature. I
can look up the menu number if you can't find it.

Also, you posted on the gizmo group that you were considering the
higher voltage PP784 controller as a replacement if needed. Section 5
of the manual shows that the voltage rang of the PP745 is 14.5-75V and
for the PP784 is 43.0-100V. Given that the PP745 won't pull in the
contactor above 70V, my guess is that the PP784 won't pull in the
contactor above 95V. FWIW, I have not yet seen below 56-57V under a
1.5C load with my 2P20S LFP at 87% DOD.

End of Original Messages 8 and 12

------------------------------



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Discussion Starter #4
Jeff, your suggestion has been implemented. The rain finally stopped and I was
able to swap cables at the controller. Good reverse, no forward. I await your
word on the replacement NOS controller.

thanks
fred
------------------------------


Repeat of Original Message: 8
Date: Wed, 15 Sep 2010 14:56:22 -0700 (PDT)
From: Jeff Major <[email protected]>

Hi fred,

For starters I'd switch the field wires, F1 and F2, and see if the motor then
runs the opposite direction. If the problem follows and reverse on the
controller still cogs even when that is actually forward on the motor, then I
think we can conclude it is a controller problem.

I may have a lead on a Sevcon 400 amp version, NOS.

Regards,

Jeff M

End of Repeat of Original Message: 8
------------------------------




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Discussion Starter #5
fred <[email protected]> wrote:
> David, I'm not sure what I'd be looking for and once I found it (in the
> calibrator) what it would mean. Joe from Sevcon said if I tried to run in
> reverse too much, I'd burn out the field coils, so I'm thinking that if the
> controller is at fault, it's pumping huge currents where there should be none.
> I did notice that the CycleAnalyst had the ammeter portion ripping along when I
> selected reverse, so I stopped that pretty quickly.

It would show you what the current through the field was. It should be
no more than 50A and that should only be when the armature had full
current. Given that when you switched the F1 & F2 wires and the motor
works in reverse but not forward it is probably something in your
controller. There are two parts. The part where the Molex connectors
are is a removable module. It is possible that the module has the
issue _or_ the controller has the issue. It would be nice to know
which and if you can get one part without the other and save a little.

If you can't find a 48V controller but can find the 72V model let me
know. I've considered getting the higher voltage controller at some
point since I could charge to a slightly higher voltage than 3.5vpc
and still have the controller be happy. Maybe I could run the higher
voltage controller and send you my 48V one.

BTW, I recommend you go through all the settings with the calibrator
and write them down so you can set up your repaired/replaced
controller with the proper settings. I believe the field resistance is
the most critical number but some other motor knowledgeable people on
this list may be able to answer you better on this.

--
David D. Nelson
http://evalbum.com/1328

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Discussion Starter #6
I was told that a new 80v controller had a two-month lag time on delivery, and
now that I've learned my controller and DC/DC converter can handle up to 75v,
I'm happy to stay with the 48v version. I'm hoping that Jeff's lead on a NOS (or
even a used) controller will pan out. The resources to have this controller
examined, fixed or replaced are limited. My first contact hasn't returned my
calls, so I'll be trying the second one, but if Jeff comes through, I'm just
going to grab the one he'll have. If I can later get this broken one repaired,
I'll have a spare perhaps.

I've recorded my controller settings on a spreadsheet from some time ago, for
the very reason you describe, as a reference in case something got messed up.


------------------------------

Original Message: 11
From: David Nelson <[email protected]>

fred <[email protected]> wrote:
> David, I'm not sure what I'd be looking for and once I found it (in the
> calibrator) what it would mean. Joe from Sevcon said if I tried to run in
> reverse too much, I'd burn out the field coils, so I'm thinking that if the
> controller is at fault, it's pumping huge currents where there should be none.
> I did notice that the CycleAnalyst had the ammeter portion ripping along when
I
> selected reverse, so I stopped that pretty quickly.

It would show you what the current through the field was. It should be
no more than 50A and that should only be when the armature had full
current. Given that when you switched the F1 & F2 wires and the motor
works in reverse but not forward it is probably something in your
controller. There are two parts. The part where the Molex connectors
are is a removable module. It is possible that the module has the
issue _or_ the controller has the issue. It would be nice to know
which and if you can get one part without the other and save a little.

If you can't find a 48V controller but can find the 72V model let me
know. I've considered getting the higher voltage controller at some
point since I could charge to a slightly higher voltage than 3.5vpc
and still have the controller be happy. Maybe I could run the higher
voltage controller and send you my 48V one.

BTW, I recommend you go through all the settings with the calibrator
and write them down so you can set up your repaired/replaced
controller with the proper settings. I believe the field resistance is
the most critical number but some other motor knowledgeable people on
this list may be able to answer you better on this.

--
David D. Nelson
http://evalbum.com/1328

End of Original Message: 11

------------------------------



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