Hi,
For cable insulation resistance calculation, the equation goes:
IR = K * log (D/d) [megaOhm-1000ft]
where D = diameter of insulated conductor
and d = diameter of copper inductor
ICEA has some K numbers for PVC and rubber. But how is K calculated? It's nowhere explained. I've come...
I didn't know the type of motor would be important in this case. I just wanted the voltage supply to the motor to be controlled without much manual operation. I don't know what type of motor this cooler has, I'll have to check with the manufacturer.
I was thinking of a simple board with a...
The motor takes up to about 60VAC and 3.5A single phase. This non-manually adjustable voltage is a preferred method for future end users to run the cooler without spending a lot of time paying attention to the ambient temp and adjusting the cooler voltage themselves.
It could potentially...
Hi,
I have a cooler powered by a small motor. The cooler motor is adjustable 0-60V (the higher voltage, the colder the cooler gets). Since a soft start is preferred, I use a typical Variac to slowly turn the voltage up in the lab.
However, I'd like to set up a simple input/output system...
Sorry, I don't know any more details regarding the specifics on how the cooler runs.
Yes, in reality I think it's alright if the cooler runs less efficiently for a few hours if the backup source doesn't fit that +/-0.5Hz. But my boss would rather know the different options that allow it to...
Thanks again, itsmoked. With regard to this cooler...as far as I understand, there's a linear motor that drives a magnet ring. This magnet ring makes the piston oscillate back and forth with respect to the displacer in the cooler, and there's a certain degree of phase shift between the piston...
Hi,
This is kind of a "spin-off" thread from the other one that I posted before.
http://www.eng-tips.com/viewthread.cfm?qid=188842&page=3
I have a 2kW Sterling cooler load that needs a backup system, and the performance drops off sharply outside 60Hz +/- 0.5Hz.
Besides UPS, "Itsmoked"...
Sorry about being ambiguous in my previous posts. I'm trying to have a backup system to keep 10 units of Sterling cooler (200W each) running. Each sterling cooler only requires about 100V/2A single phase.
So I'm only looking for a small generator, 2kW or so, not an industrial type of...
So is there some kind of frequency regulator that I can add to the output to make sure it stays within 60Hz +/- 0.5Hz?
I've looked at frequency converters that can take 47-63Hz input and output 60Hz +/- 0.1Hz. But those are really expensive (~$3,000).
Any other cheap (less than $500)...
For a diesel backup generator, what's the typical output frequency variation? I've read specs that say 60Hz +/- 5%. Is it typcially off by that much?
In my application, the load is very sensitive to frequency variation. The performance starts dropping when it's outside of 60Hz +/- 0.5Hz...
I'm looking for a cheap current limiting device that will cap the current at 25mA from the 120V wall plug. I read that a PTC thermistor would do what I'm looking for.
Has anyone dealt with thermistors? I guess I just need to look for one that allows normal operating current at 25mA, and...
The load, AC, and DC are all connected with ground wire for return path. I was just trying to show a rough presentation, and the text sketch didn't show up well.
I'd like to superimpose AC and DC sources into one wire for simulation on a smaller scale (100-120V AC&DC). I have a DC power supply to control the DC voltage output, and perhaps get 120VAC from the wall. My load has a choke that can filter up to 1000VAC and the rest of the device can take...
