Is there any evidence of ventilation devices?

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blake121666
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Re: Is there any evidence of ventilation devices?

Post by blake121666 » Tue Jan 15, 2019 9:41 pm

I think Rudolf possibly explained what is going on here. This is not how Mattogno described it though. Here is a possible solution to this puzzle we're dealing with.

The fans are all rated at a standard pressure of 40 mm water column. And the speed, w, is given as the speed under THAT pressure. Higher pressure and it will spin slower. Lower pressure and it will spin faster.

So two fans with the exact same specs will spin faster or slower when put into different environments (under different pressure loads). And they would therefore move more or less air according to that environment.

I think THIS is what is being discussed here.

Under this model I have described here, the speed of the fan, w, would be a result of the horsepower of the motor MINUS the pressure of the environment in which it is in. And of course in an enclosed space: higher "w" would give larger airflow but result in greater pressure - requiring a higher "T".

I think this would explain it. Is this a correct analysis, Scott (or anyone else who might know)?

What totally confused me is that Mattogno kept speaking about the fans as if they'd always spin at their rated speed - IN ANY ENVIRONMENT. I think this is untrue and the case is probably what I've said here. This implies to me that fans are built to have different T and w. T for the pressure and w for the airflow. Higher pressure requires higher T for the same w. And larger w requires larger T for the same fan.

This is kinda what I've thought all along. But I'm no expert on fans. I just know that what Mattogno says throughout his article simply HAS to be wrong. I don't think I'm misunderstanding his article. He is treating w as constant in all environments in that article. It's constant in that it doesn't change in any given environment but it is different for different environments.

There might be efficiency and other considerations but I think this is the basic gist of the matter here.

EDIT: If we have 2 motors with the same rated HP, the 8000 cbm per hour motor has a higher "w" (spins faster) and lower T (lower pressure difference) than the 4800 cbm per hour fan. So one needs to know the pressure in the ducts to determine what difference there would be airflow-wise between the 2 3.5 HP motors with the same fan.

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Re: Is there any evidence of ventilation devices?

Post by Scott » Wed Jan 16, 2019 4:33 am

Yes, I think that is right. I think they are trying to say that AC motors do not run at a rotation frequency above the mains supply, but Mattogno may have confused the synchronous and asynchronous type or other configurations possible. These are not likely "clock" motors that run at the same speed governed by the AC mains, and they are not going to run unloaded, either.

Another possibility is that Universal AC/DC motors are very often used for appliances and for blower fans, although since they have armatures with mechanical commutators and brushes and are less efficient, they are not usually found in applications larger than a fraction of a horsepower. However, Universal motors can run very fast and be very powerful, with a lot of starting torque:


Image
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https://en.wikipedia.org/wiki/Universal_motor

Even when used with AC power these types of motors are able to run at a rotation frequency well above that of the mains supply, and because most electric motor properties improve with speed, this means they can be lightweight and powerful.[5] However, universal motors are usually relatively inefficient: around 30% for smaller motors and up to 70–75% for larger ones.[5] [Torque-speed characteristics] Series wound electric motors respond to increased load by slowing down; the current increases and the torque rises in proportion to the square of the current since the same current flows in both the armature and the field windings. If the motor is stalled, the current is limited only by the total resistance of the windings and the torque can be very high, and there is a danger of the windings becoming overheated. [...]


I think it is fair to assume that we are dealing with brushless AC Induction (asynchronous) motors for the blower fans here given the very large size of 2.5 HP cited, but those are not the only motor options and speeds possible. Multipole-wound options would be another possibility for running at different shaft speeds given the AC mains frequency, for example.


Three Phase 2.5 HP AC Induction Motor,
Poles - 2/4/6, RPM-3000, Type-Squirrel Cage Rotor ...


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Re: Is there any evidence of ventilation devices?

Post by Huntinger » Wed Jan 16, 2019 6:52 am

Scott wrote:
Wed Jan 16, 2019 4:33 am
I think it is fair to assume that we are dealing with brushless AC Induction (asynchronous) motors for the blower fans here given the very large size of 2.5 HP cited, but those are not the only motor options and speeds possible. Multipole-wound options would be another possibility for running at different shaft speeds given the AC mains frequency, for example.
I am not an expert on electric motors but have built one which functions. This is a great thread but perhaps a little off topic in the fact the topic is about ventilation systems which is presumably to disperse gas, particularly ZyklonB. I am unsure if the state of knowledge regarding electric motors 73 years ago is the same as now? It would also seem that perhaps the modern motors run on a regular power supply and not the generated one at Birkenau. Perhaps someone may give an inkling as to the actual power generation of that camp?
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Re: Is there any evidence of ventilation devices?

Post by blake121666 » Wed Jan 16, 2019 6:09 pm

Huntinger wrote:
Wed Jan 16, 2019 6:52 am
Scott wrote:
Wed Jan 16, 2019 4:33 am
I think it is fair to assume that we are dealing with brushless AC Induction (asynchronous) motors for the blower fans here given the very large size of 2.5 HP cited, but those are not the only motor options and speeds possible. Multipole-wound options would be another possibility for running at different shaft speeds given the AC mains frequency, for example.
I am not an expert on electric motors but have built one which functions. This is a great thread but perhaps a little off topic in the fact the topic is about ventilation systems which is presumably to disperse gas, particularly ZyklonB. I am unsure if the state of knowledge regarding electric motors 73 years ago is the same as now? It would also seem that perhaps the modern motors run on a regular power supply and not the generated one at Birkenau. Perhaps someone may give an inkling as to the actual power generation of that camp?
The Physics hasn't changed. Mattogno is relying too strongly on the fact that an unloaded induction motor will spin at a constant speed determined solely by the frequency of the input power. But a fan is not merely an unloaded induction motor. Even if the motors for the fans in question were induction motors, those induction motors are made to spin at pre-determined speeds by tweaking the output torque - which could have been achieved at the time in a number of ways (rotor windings most likely).

So it appears to have been the case that the fans in question here all have their specs given for a standard pressure. For instance, for this originally planned fan for K2: under 40 mm water column pressure, the fan would spin at a rate that a 1.6 HP / 925 rpm (unloaded) motor spins it. And they figured that in the given environment (the load on this motor), that would result in an airflow rate of 4800 cbm per hour.

But of course the choice of the fan and motor was based on the desired airflow rate and what the load on it was figured to have been. If they wanted a higher airflow rate they would have chosen a higher horsepower motor (if using the same fan). Similarly, if the load on the motor was more than as figured, the airflow rate would be less than they figured. To achieve a higher airflow rate than what they got, they'd need to choose a higher horsepower motor (if using the same fan).

We don't have enough info to know whether a higher horsepower motor (3.5 HP vs 2.0 HP - both assumedly with the same fan) was chosen because of the load on the motor or to increase the airflow rate.

EDIT: This is the understanding Mattogno explains which I claim is untrue:
Mattogno, section IV wrote:In the cost estimate of November 4, 1941, 925 revolutions per minute instead of 1,000 [the unloaded speed of a 6-pole induction motor] were indicated, because the rotor does not rotate at the same speed as the stator magnetic field, but at a speed slightly lower (due to mechanical and cooling losses); the difference between the stator speed (synchronic speed) and the speed of the rotor, known as run rate of flow, is set between 3% and 7%. The effective speed, and therefore the effective number of revolutions, results, consequently, as a little lower. In our specific case the rate of flow was calculated at 7.5%: 1000 – (0.075 x 1000) = 925 revolutions/min.
I claim that those motors are not that simple. Those motors are pre-determined to spin at 925 rpm under some baseline fan load and their torques are adjusted to achieve that. The fan load determines the torque desired. And the fan itself does not spin at the motor speed. The motor slows down based on the load from the fan.

So for this particular fan he is discussing, if it was an induction motor, I claim that it was a 2-pole or 4-pole induction motor whose torque was tweaked so that it spun at 925 rpm. It probably was not a 6-pole induction motor with simply "mechanical and heat losses".

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Re: Is there any evidence of ventilation devices?

Post by blake121666 » Wed Jan 16, 2019 7:35 pm

Actually, it looks like I didn't read that initial estimate correctly. Here is the google translate of it:

Image

So it is saying that for the given fan to produce 4800 cbm per hour against a pressure of 40 mm water column it needs a 1.6 HP output motor rated for 925 rpm.

The motor to be used was a 380 volts / 50 Hz / 3-phase motor of 2.0 HP and unloaded speed of 925 rpm.

I wish I had translated this to begin with. It makes it clearer to me the separation between the requirements of the fan and the motor chosen for that fan to satisfy those requirements. I formerly read it as a 1.6 HP fan - which looks to be wrong.

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Re: Is there any evidence of ventilation devices?

Post by Huntinger » Wed Jan 16, 2019 9:26 pm

It does seem that ventilation fans were used in the Leichenkellers, which is necessary to stop the build up of stale air due to decomposition: the assumption now by the hoaxers is that these same fans could have been used to extract lethal quantities of Zb Hydrogen Cyanide gas as well in a timely manner. If the Leichenkellers were indeed used as gaskammer there would be no need for a separate extraction system. It would be assumed that prior to the mass gassing the furnaces would be in full swing. From my understanding these had large fans to act as a kind of blast furnace, all one would need is pipes to the chimneys below the fan I guess and open a valve to the Leichenkeller and presto all of the poison goes up the chimney of the Krema sucked out by the large fans.
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Re: Is there any evidence of ventilation devices?

Post by blake121666 » Thu Jan 17, 2019 2:25 am

Here we go. I didn't notice Mattogno had a scan at the article for the motor we're having a hard time figuring. Here it is. And here's my google translate of the 1st 3 things on the list:

Image

This motor has a double armature ("Doppelnutanker"). This suggests to me that it is not an AC induction motor. Or if it is, then it is a double-slip induction motor - both stator and rotor are tweaked for higher torque.

So the first fan needs 1.6 HP to generate 4800 cbm per hour against a pressure of 40 mm WC with an adjusted speed of 925 rpm.

The second fan needs 2.9 HP to generate 8000 cbm per hour against a pressure of 40 mm with an adjusted speed of 925 rpm.

We need to figure out what the actual torque for these requirements was for each motor that was actually used and then I'll tell you how fast each actually spun and what the respective airflow rates were. I'll have to think this one through and get back to it. The actual motors used were for the first fan 2.0 HP and the second fan 3.5 HP. We need to figure out the loads on each of these fans.

It's going to be in the neighborhood of what they are saying there of course. The first one was probably around 4800 cbm per hour and the second around 8000 cbm per hour. Why else would they write that?

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