Test Equipment Anonymous (TEA) group therapy thread

[tonyalbus]

This may come as a dumb question, but isn't there any documentation available which is describing the function of this gear?
Including how the air should flow?   

Not a dumb question. A quick googlefu found nada.

Hot air goes up.... just help the flow...

[VK5RC]

Not test equipment but has been a project.
A second battery for a small car fridge (Engel 14 l - refrigerator type). I had a spare lab power supply head unit and a boost dc-dc converter, to boost car voltage up to charge the battery and run the fridge and a disconnect relay to cut off the battery from running the psu unit when the ignition is switched off.
The battery is a 12AHr Lifepo4 type and has survived a few afternoons in a car in the sun. The unit is mounted in an el cheapo tool box for bouncing around the back of the car.
Nice to come back to a cool drink at a reasonable price!

[med6753]

In Swedish with little information......

http://w140.com/tekwiki/wiki/FB310

[Robert763]

[/quote]

To reverse  the motor you don't flip the bearings. You flip the stator. Take the rear bearing mount off, slide the stator off, flip the stator about its vertical axis so the lamination that was facing away from from the fan is now facing it. Put rear bearing mount back on.
This works bcause the shaded pole of the stator is nowon the other side of the rotor axis.


OK, got it. And that means I will have to splice wire to the motor leads to be able to reach the terminal strip.....correct?
[/quote]

I can't tell from here or the photos but they may still reach.

[Specmaster]

B&Q do a nice line of screwdrivers which will come out of the other side of your victim 

I have a set of screwdrivers that have 330mm long blades, they would most certainly protrude through a torso for sure.

[Specmaster]

This may come as a dumb question, but isn't there any documentation available which is describing the function of this gear?
Including how the air should flow?   

To me a simple rule...HOT air goes up...
the fan is below.... the fan should be pushing not to pull against the natural flow

Tony, you are correct, the fan should assist the natural air flow and thus improve the thermal dissipation. Doing it the other way around is just downright dumb as it will retain more heat inside the scope enclosure.

[PA0PBZ]

Tony, you are correct, the fan should assist the natural air flow and thus improve the thermal dissipation. Doing it the other way around is just downright dumb as it will retain more heat inside the scope enclosure.

Also, you would put a filter at the input side, not at the air output.

[bd139]

Also, you would put a filter at the input side, not at the air output.

Unless you are HP's PC division, at which point it is best to bring a shovel when you open the PC

(just found out Z8 doesn't have any filtering  )

[Specmaster]

@med, if you look at your photo that shows the motor and the Swedish photo of the same view, your windings/laminations are correct so is the fan blade. All you now need to do is to ensure that the blade rotates clockwise when viewed from the angle of the attached photo, if it is job done, then you can decide about the noise level.

[BU508A]

In Swedish with little information......

http://w140.com/tekwiki/wiki/FB310

This could be a hint about the rotation direction:

[med6753]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case. And I verified that anyway.

[Specmaster]

Gah on that I was just watching this 

<SNIP>

This guy is the FPV equivalent of ElectroBoom; a complete fucking moron. You don't run any modern BL motor without a prop; they're too high performance. The ESC loses necessary commutation feedback and goes out of sync, and then you wind up with a LO side FET still biased on when the next commutation fires the HI side, and POOF! Dead short through the windings and fire. If not, then the bell grenades as the magnets are only held in place with machined slots & epoxy.

I wish I had that kind of money to waste making myself look like an idiot. 

mnem
 

I was going to say that I didn't think he had any blade on that motor, so apart from the loading aspect on the rotor, there was also zero cooling effect on the motor either.

If you have a series wound motor and you run the motor with no form of mechanical loading then as long as the power is applied to the motor it will keep accelerating until the motor suffers serious mechanical damage or even total destruction, much same as a runaway diesel engine, very frightening thing to be around.   

<SNIP>

It's not true that a series wound motor will accelerate to destruction with no load. They will all accelerate until the back EMF generated by the rotation equals the apparent applied voltage (actual applied voltage minus voltage drop across winding and brush resistance). The problem is that this speed may be higher than the mechanical speed limit. In this case the motor may be damaged. Loading the motor increases the resistive voltage drop, reduces the apparnet voltage and thus the speed at which the back EMF equals the apparent voltage. Many conventional car starter motor fall into this category. However if you run them at lower voltage they will stabilse at a safe speed.
For a DC motor speed is proportional to apparent voltage and torque is proportional to current. Note the "apparent" voltage condition, i the motor has zero resistance this is the applied voltage but most of us don't have access to superconducting motors. It is the voltage drop across the intternal resistance that causes a DC motors speed to drop with load. If you put a posive feed pack loop in the supply to compensate for the resistive voltage drop the motor speed will remain constant regardless of load variation. I've designed systems that do exactly this. 

Actually I was talking about AC industrial-sized motors, not DC ones, but ones actually doing a proper industrial job of work, and they will destroy the bearings to the point that they collapse and the rotor then impacts on the stator at such force that it can actually destroy the motor beyond repair.

[Robert763]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case. And I verified that anyway.

You beat me to it, the stator in the Techwiki photos looks identcal to yours.
The motor similarity does not change the fact that the fan blade shape, filter postion, normal rules of cooling an common sense (don't blow air at operator) all indicat it should rotate th other way and suck air in.
The problem is I can't see the shaded pole in any of the photos. It's normally a copper rod loop or plate.
Can you post a photo of the pole piece?

[Specmaster]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case. And I verified that anyway.

Then something is clearly wrong, the only way that can push air out the front is if, looking from within the enclosure, looking at the motor the blade must be spinning anticlockwise, in which case either rotate the windings or remove the blade, flip it 180 degrees and refit with the blade towards the motor bearing

[Robert763]

Gah on that I was just watching this 

<SNIP>

This guy is the FPV equivalent of ElectroBoom; a complete fucking moron. You don't run any modern BL motor without a prop; they're too high performance. The ESC loses necessary commutation feedback and goes out of sync, and then you wind up with a LO side FET still biased on when the next commutation fires the HI side, and POOF! Dead short through the windings and fire. If not, then the bell grenades as the magnets are only held in place with machined slots & epoxy.

I wish I had that kind of money to waste making myself look like an idiot. 

mnem
 

I was going to say that I didn't think he had any blade on that motor, so apart from the loading aspect on the rotor, there was also zero cooling effect on the motor either.

If you have a series wound motor and you run the motor with no form of mechanical loading then as long as the power is applied to the motor it will keep accelerating until the motor suffers serious mechanical damage or even total destruction, much same as a runaway diesel engine, very frightening thing to be around.   

<SNIP>

It's not true that a series wound motor will accelerate to destruction with no load. They will all accelerate until the back EMF generated by the rotation equals the apparent applied voltage (actual applied voltage minus voltage drop across winding and brush resistance). The problem is that this speed may be higher than the mechanical speed limit. In this case the motor may be damaged. Loading the motor increases the resistive voltage drop, reduces the apparnet voltage and thus the speed at which the back EMF equals the apparent voltage. Many conventional car starter motor fall into this category. However if you run them at lower voltage they will stabilse at a safe speed.
For a DC motor speed is proportional to apparent voltage and torque is proportional to current. Note the "apparent" voltage condition, i the motor has zero resistance this is the applied voltage but most of us don't have access to superconducting motors. It is the voltage drop across the intternal resistance that causes a DC motors speed to drop with load. If you put a posive feed pack loop in the supply to compensate for the resistive voltage drop the motor speed will remain constant regardless of load variation. I've designed systems that do exactly this. 

Actually I was talking about AC industrial-sized motors, not DC ones, but ones actually doing a proper industrial job of work, and they will destroy the bearings to the point that they collapse and the rotor then impacts on the stator at such force that it can actually destroy the motor beyond repair.

 

They don't make series wound AC motors.
The nearest is a brushed "universal" (AC/DC) motors that are used in small medium power applinaces like drill and grinders. These are not "industrial sized" nor do they destroy themselves off load.
AC motor speed is set by the number of poles and supply frequency.

[Brumby]

This is the typical arrangement for efficient acceleration of air.  The leading edge has a low angle of attack allowing the blade to slice into the air with minimal turbulence - and minimal noise.  The blade then curves away, accelerating the air in the direction shown.

The pictures you show, Med, look perfectly correct - if the fan draws air IN.

[Robert763]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case. And I verified that anyway.

IMPORTANT UPDATE!
Looking again at the photo of your motor outside the case the wires comut the RIGHT side of the centerline (viewed from the rear) on the TekWiki photos (and looks like in on you installed photos) the wires come out of the LEFT side.

The stator is on backwards.

[Brumby]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case.

I is confoozed ....  How can the air blow OUT the front if the fan spins clockwise when viewed from inside the case? ? ?

[Specmaster]

Guys....look at that photo from Tekwiki and compare it with how I initially set up mine. IDENTICAL. And guess what......set up that way IT PUSHES AIR OUT THE FRONT.

Edit, I found the direction arrow on mine. SAME. Spins clockwise when viewed from inside case. And I verified that anyway.

Then it is spinning the right way and that means with that blade, it has to be sucking air in from the front, not blowing it out.

[Brumby]

The stator is on backwards.

I'm leaning towards this being the fundamental issue.

How to fix? - Reverse the stator.

There are two ways of doing this:
 1. Spin around vertical axis, swapping left and right
 2. Spin around horizontal axis, swapping top and bottom

I'm thinking option 2 is the better approach as it avoids this issue:

.... And that means I will have to splice wire to the motor leads to be able to reach the terminal strip.....correct?

[xrunner]

It wouldn't be designed to blow air into a filter, you want to pull air through a filter before supplying it to the equipment ... 

[BU508A]

Since page 2968 we are discussing airflow and fan directions ... looks like a really tough problem, though.    

[Specmaster]

Guys, the way that med has his motor and blade set, is EXACTLY the same as the tekwiki photos, look at following photos, the top on is meds, second one if tekwiki. Med has confirmed that the motor when viewed from the rear is clockwise as per direction arrow on the motor bracket, the blade is the same, therefore Med's has to be sucking air IN and not blowing, the blades are the correct way round for that rotation.

[Specmaster]

Gah on that I was just watching this 

<SNIP>

This guy is the FPV equivalent of ElectroBoom; a complete fucking moron. You don't run any modern BL motor without a prop; they're too high performance. The ESC loses necessary commutation feedback and goes out of sync, and then you wind up with a LO side FET still biased on when the next commutation fires the HI side, and POOF! Dead short through the windings and fire. If not, then the bell grenades as the magnets are only held in place with machined slots & epoxy.

I wish I had that kind of money to waste making myself look like an idiot. 

mnem
 

I was going to say that I didn't think he had any blade on that motor, so apart from the loading aspect on the rotor, there was also zero cooling effect on the motor either.

If you have a series wound motor and you run the motor with no form of mechanical loading then as long as the power is applied to the motor it will keep accelerating until the motor suffers serious mechanical damage or even total destruction, much same as a runaway diesel engine, very frightening thing to be around.   

<SNIP>

It's not true that a series wound motor will accelerate to destruction with no load. They will all accelerate until the back EMF generated by the rotation equals the apparent applied voltage (actual applied voltage minus voltage drop across winding and brush resistance). The problem is that this speed may be higher than the mechanical speed limit. In this case the motor may be damaged. Loading the motor increases the resistive voltage drop, reduces the apparnet voltage and thus the speed at which the back EMF equals the apparent voltage. Many conventional car starter motor fall into this category. However if you run them at lower voltage they will stabilse at a safe speed.
For a DC motor speed is proportional to apparent voltage and torque is proportional to current. Note the "apparent" voltage condition, i the motor has zero resistance this is the applied voltage but most of us don't have access to superconducting motors. It is the voltage drop across the intternal resistance that causes a DC motors speed to drop with load. If you put a posive feed pack loop in the supply to compensate for the resistive voltage drop the motor speed will remain constant regardless of load variation. I've designed systems that do exactly this. 

Actually I was talking about AC industrial-sized motors, not DC ones, but ones actually doing a proper industrial job of work, and they will destroy the bearings to the point that they collapse and the rotor then impacts on the stator at such force that it can actually destroy the motor beyond repair.

 

They don't make series wound AC motors.
The nearest is a brushed "universal" (AC/DC) motors that are used in small medium power applinaces like drill and grinders. These are not "industrial-sized" nor do they destroy themselves off load.
AC motor speed is set by the number of poles and supply frequency.

It might well have been a slip ring motor, it was years at college when this happened, and we had all these motor setups at the back of the classroom for experiments and one day we went into the lab/workshop for lessons and this particular motor had exploded / broke up whatever and there were bits it embedded in the ceiling, walls and the floor and the lecturer told us all that it was series a series motor and it was run of load, that was 50 years ago.

[Zucca]

just put a noctua and done