Can the Vectrix Cooling Impellers safely run at lower or higher speeds?

9 posts / 0 new
Last post
Mik
Mik's picture
Offline
Last seen: 5 years 1 month ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Can the Vectrix Cooling Impellers safely run at lower or higher speeds?

A thread to discuss the ins and outs of the Vectrix VX-1 battery cooling impellers.

Mik
Mik's picture
Offline
Last seen: 5 years 1 month ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

I have been playing around with the impellers in various attempts to slow them down a bit.

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=8722&start=0

http://endless-sphere.com/forums/viewtopic.php?f=14&t=8794&start=0

http://visforvoltage.org/forum/7471-abcool-40-vectrix-auxiliary-battery-cooling-system#comment-42809

Here is the datasheet for the impellers: http://www.comairrotron.com/cgi-bin/dcimpellerdatasht.pl?Pnum=039829&voltage=&airflow_val=&airflow_unit=CFM&pressure_val=&pressu...

In private messages there were some concerns expressed that the impellers are not capable of safely running at lower or higher voltages than 12V.

I found out today that the company who made the impellers, Comair, has gone bankrupt!
I was told that "EBM" would be a good starting point to try to find replacement impellers if needed.

That makes it kind of important to not fry the impellers in a great hurry...

That said, I was told by the person answering the phone at the North American Sales Office ( +1.479.426.5521 )
that my interpretation of the data sheet is correct, i.e. the impellers are designed to be run with voltages between 7V and 15V.

I have also already run them for several hours (cumulatively, up to 1 hr at a time) at low voltages, and for a few seconds at up to 15V, with no apparent damage or problems.

However, The Laird has some strong concerns and might well be right. He has also taken the impellers apart and sent me some photos which I will post below.

Here is some of what he wrote:

Hi Mik,

The motor is built as a fixed speed motor. This is a sophisticated system
and is designed to protect the motor from all abuses. (Have you noticed if
you have a motor powered and running and just flick the power off and
immediately back on. The motor actually slows to a virtual stop and them
restarts again as if it is checking the power supply before continuing. (I
still think that it is 'overkill'))

The only speed adjustment possible (without risk of damaging it) is by way of
their own built in system which is only available as an optional extra.

The motors Vectrix have used appear to NOT have this option. I have checked
the link you gave and I note that if you tick the box for the 'Impellor speed
control option' it opens up a list of different ways by which the speed may
be controlled. It also shows the possible different outputs for the
tachometer terminal.

What is happening when you supply the motor with more or less voltage is that
the electronics tries to compensate for the difference. It will allways
attempt to draw 30 Watts so less voltage equates to more current and visa
versa. Always the voltage multiplied by the current = 30 Watts and the motor
speed will try to remain constant. More current tends to eqate to more heat
(P=I x I x R) in resistive components, I would be disinclined to use less
than the twelve volt supply, in fact more voltage might even give an increase
in the motors life due to the lower currents being used.

The motors can be openned and re assembled. With the motor side up. prise
off the black disk in the centre (it's about an inch accross) under that is a
tiny circlip on the shaft. Remove this (be careful there is a washer and
spring trying to escape) remove the washer and spring and then simply pull
the motor and impellor apart. Re assemble in reverse (obviously).

If you want to get at both sides of the printed circuit board remove the
large nut from the central tube where it passes through the coil arrangement
and withdraw the p.c.b. and coils from the alloy housing. BE VERY careful
with the wires, release them from their 'trapped' possition and feed them
gently through the alloy housing.

I will point out that without a circuit diagram this is unlikely to be a
useful exercise. Because there are various options for speed control (and no
indication of how much control is possible) the parts by which speed control
is possible are very likely missing / not fitted.

The power supply / charger D.C. to D.C. converter. Yes there is a D.C. to
D.C. converter built into the power supply. I have no knowledg of it's
potential output but being as it is possible to power both headlight
fillaments at once (built into the software) and the headlight fillaments are
30 Watts each, in addition to which there is a 500mA 'auxilliary socket' in
the glove compartment, I would think that it would be acceptable to draw as
much as 1 Amp indefinately or 2 Amps for short ( 2/3 minutes, maybe longer)
periods, all at twelve volts of course. (If you ran with the headlight
turned 'OFF', then you could draw 3 Amperes comfortably).

You may publish any of the pictures and information which I have provided and
if you wish to add my 'nom de plume' you may do so.

I have also modified the headlight casing to make it easier to carry out
headliht 'aiming' adjustments and I am working on an 'equalising charger'
which will not damage the battery (well not as much as Vectrix's equalising
does anyway). I am afraid I am a bit slow with some of this, lots of other
things demanding my time.

Keep in touch, best wishes,

The Laird

Here are the pictures:
Photobucket

Photobucket

Photobucket

Or click on the thumbnails for full resolution pictures:

//i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/ABCool/th_dsc_0157a.jpg) //i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/ABCool/th_dsc_0165a.jpg) //i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/ABCool/th_dsc_0165b.jpg)

..

..

So, what do you all think of this? Are these impeller motors designed for lower voltages or will they get damaged by it?

This information may be used entirely at your own risk.

There is always a way if there is no other way!

AndY1
AndY1's picture
Offline
Last seen: 7 years 9 months ago
Joined: Tuesday, June 17, 2008 - 04:29
Points: 1071
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

I think they might not even turn on at lower than specified Voltage.

Mik
Mik's picture
Offline
Last seen: 5 years 1 month ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

I think they might not even turn on at lower than specified Voltage.

Oh yes, they do turn on!

When the voltage gets too low (around 7.5V) they turn off; that lets the voltage recover a bit, so one impeller starts up for a few seconds until the current draw again drops the voltage too far, and it turns off again, etc. etc. etc.

This information may be used entirely at your own risk.

There is always a way if there is no other way!

AndY1
AndY1's picture
Offline
Last seen: 7 years 9 months ago
Joined: Tuesday, June 17, 2008 - 04:29
Points: 1071
Re: Can the Vectrix Cooling Impellers safely run at lower or ...
I think they might not even turn on at lower than specified Voltage.

Oh yes, they do turn on!

When the voltage gets too low (around 7.5V) they turn off

That's what I meant, by saying, 'when the Voltage goes under specified Voltage' (7V-15V) ;-)

myocardia
Offline
Last seen: 11 years 2 months ago
Joined: Friday, November 7, 2008 - 04:07
Points: 104
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

Mik, it is completely safe to operate any and all DC electric motors with less than their "rated" voltage. I, like many other people, have ran 12V DC fans @ 7V for multiple years, never experiencing a single failure. If it weren't possible, no electric vehicles would be capable of having throttles.;-) We would have to operate them all with simple on/off switches, with the electric motors receiving either 0% or 100% of the available battery voltage.

All of these fans will run quite happily while receiving 7V, except possibly the one with only a 500 RPM speed @ 12V. Although knowing Scythe, the 500 RPM @ 12V fan will most likely still quite happily start spinning @ 7V.

Mik
Mik's picture
Offline
Last seen: 5 years 1 month ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

Well, the theoretical problem is related to the built-in controller, not the motor as such.

I do not think it actually happens with this motor, but could you not theoretically get the same problem that occurs when the Vectrix rear light blows due to under-voltage?

Some IC ramps up the amps to keep the wattage the same at the lowered voltage and overheats, and fries.

This information may be used entirely at your own risk.

There is always a way if there is no other way!

ElectricLou
ElectricLou's picture
Offline
Last seen: 1 year 1 week ago
Joined: Wednesday, January 9, 2008 - 16:11
Points: 59
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

Mik,
Your worries are warranted. Some electronically controlled motors will increase the current to keep the motor up to it's programmed speed. This type of motor may self destruct under low voltage conditions. An easy way to tell if the vectrix impeller motor will be damaged is to measure the current on one motor at it's rated voltage. Slowly reduce the voltage while monitoring the current. If the current increases at the lower voltage, it is a safe bet that running it at a lower voltage will stress the electronic switching components. In some electronic motors the current will decrease with the voltage and no harm will come to those motors (as long as you do not reduce the voltage so much that the motor will not start).

It all depends on the design of the motor, some have feedback to maintain rpm, others run wide open and applied voltage determines rpm.

Mik
Mik's picture
Offline
Last seen: 5 years 1 month ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Re: Can the Vectrix Cooling Impellers safely run at lower or ...

Mik,
Your worries are warranted. Some electronically controlled motors will increase the current to keep the motor up to it's programmed speed. This type of motor may self destruct under low voltage conditions. An easy way to tell if the vectrix impeller motor will be damaged is to measure the current on one motor at it's rated voltage. Slowly reduce the voltage while monitoring the current. If the current increases at the lower voltage, it is a safe bet that running it at a lower voltage will stress the electronic switching components. In some electronic motors the current will decrease with the voltage and no harm will come to those motors (as long as you do not reduce the voltage so much that the motor will not start).

It all depends on the design of the motor, some have feedback to maintain rpm, others run wide open and applied voltage determines rpm.

I just found this loose end....Thank you, ElectricLou!

Unfortunately I have not managed to properly test this, although I now have a power supply which shows voltage and current at the same time (up to 36VDC and 3A).

Next time I have the seat off I'll test it!

Has anyone else tested it yet?

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Log in or register to post comments


Who's online

There are currently 0 users online.

Who's new

  • mariabella devin
  • MariahDouglas
  • venhon
  • cminter
  • Robert Feagley

Support V is for Voltage