H7225 constant voltage conditioner

[saipan59]

I'm checking out this H7225 "constant voltage conditioner" which belongs to the museum I volunteer at. Does anyone have experience with it? What type of installations would typically use one of these? It works fine, although it makes a fairly obnoxious buzzing sound - is that typical for these, or does this one have a loose lamination in the transformer? Thanks for any comments!

Pete

 

[bburley]

If the transformer has loose laminations, it may be drawing more input current than normal even with no load. I don't know exactly what it should be, but I would think very little with no load.

 

[antiquekid3]

"Drawbacks of CVTs are their larger size, audible humming sound, and the high heat generation caused by saturation."

Voltage regulator - Wikipedia

en.wikipedia.org

 

[bburley]

"Drawbacks of CVTs are their larger size, audible humming sound, and the high heat generation caused by saturation."

Voltage regulator - Wikipedia

en.wikipedia.org

That article also says "Efficiency at full load is typically in the range of 89% to 93%. However, at low loads, efficiency can drop below 60%" suggesting that the no-load current will be higher than I assumed.

 

[Chuck(G)]

That article also says "Efficiency at full load is typically in the range of 89% to 93%. However, at low loads, efficiency can drop below 60%" suggesting that the no-load current will be higher than I assumed.

Just so--they get quieter with heavier loads. Never cared for them much, as they do distort a sinusoidal waveform--but we've discussed this before.

 

[Alegend]

It works fine, although it makes a fairly obnoxious buzzing sound - is that typical for these, or does this one have a loose lamination in the transformer?

I have a similar device which is labelled a "power conditioner". It emits such a loud hum it makes you want to get up and move to another room. All that's inside is a giant transformer and two capacitors and it weighs about 25Kg.

I guess if you had expensive equipment hooked up to mains in your 80's computer room, such a voltage "smoother, stabilizer and regulator" was an easy sell.

-Alon.

 

[pbirkel@gmail.com]

We had an immense (a couple of ft^3) SOLA unit (something like one of these: https://assets.alliedelec.com/v1609412648/Datasheets/8ad8acceed300f4ed5417a38c4cc09d8.pdf) bolted to the wall to supply a PDP-8/L and associated equipment in the early 70's. Although it did hum a bit, it was pretty subdued. I don't remember it being as annoying as an overhead 4 foot fluorescent lamp fixture ballast that's not operating quite right. I expect that the cinder-block wall mounting served as a great dampener given the serious attachment (4 ~3/8" bolts). With the smaller free-standing units there's not a lot of dampening going on; instead the chassis/cover is serving as a sounding board on those rubber feet ...

 

[thunter0512]

If you have worked near a motor-generator set for a mainframe like a CDC CYBER then you wouldn't complain about a little hum from these "power conditioner" toys. To make things worse on mainframes like the CDC CYBER there was the constant 400 Hz 3 phase supply noise. I didn't bother me too much when I was younger, but it would drive me crazy now.

 

[Chuck(G)]

I do remember the 3-phase variacs in the power control panel of the 6600. With a full complement of tape drives, line printers and card gear, a computer room could be very noisy. At SVLOPS, we were issued those yellow foam earplugs. At first, the noise seems tolerable, but after a few hours, you realize that your nerves are being shredded.

But even being around 3-phase 60 Hz gear using full-wave rectification results in a "hum" of 360Hz, which is equally annoying. I remember that from a stint as projectionist with carbon-arc lamps so powered.

I recall that many old military airborne electronics ran from a 400Hz supply also.

I also worked in a steel mill where 25Hz power was used. The transformers were much larger than their 60Hz cousins and did not hum, so much as rattle.

 

[saipan59]

In case anyone is interested, the Museum has put this CVC on eBay. Pickup only in Colorado Springs.
The sale benefits a worthwhile non-profit.
eBay item number: 145747594264

Pete