compressor

[Drains]

People dislike direct drive compressors, I notice. Can anyone say why?

 

[yarpap]

very very noisy,nasty horrible things,get a good compressor and look after it and it will serve you very well and your naighbors will thank you
Dave

 

[shenion]

I had a 2.5HP direct drive compressor. (Cambel Housfeld)

Now have a 5HP belt drive. (Sears Craftsman)

So twice the power but it is half as loud. The old one shook the entire house. The Sears is probably 15 years old. Still going strong.

 

[Wozzaaah]

I've just bought a SE16c150 Got it on their VAT free offer.
Haven't used it yet, waiting for the electrician to fit the new supply to garage. Looks a nice bit of kit.

Hey! Just tried mine on a 13A plug and it runs fine! It seems to have a soft-start on it to lighten the load on the motor. Mine is also much quieter than my 2hp 50l direct drive one.

Meant to say, mine's also a Clarke SE16c150!

 

[irondarren]

People dislike direct drive compressors, I notice. Can anyone say why?

Simple enough Si, if a direct drive compressor motor goes pop, its basically junk, where as a belt driven one is far easier to replace the motor. My last compressor has 3 motors in its lifetime, each lasting about 30 months before going pop. might be something to do with the useage i give it, direct drives are always cheaper. but belt driven is easier to repair if the need be

 

[Wozzaaah]

What compressor have you got Darren?

 

[rtbcomp]

I suspect direct drive units run faster. Belt driven ones invariably have a reduction from the motor to the pump. IIRC the pump runs at about 950 rpm, a motor runs at 1440 rpm. (Simplifying things)

The higher speed means more noise and wear & tear

 

[irondarren]

What compressor have you got Darren?

battered 3hp 10cfm fad, in need of replacement, and a cheapy 1.5hp direct drive, for taking out on site if need be

 

[klaatu]

elebub, I have that Axminster one, it seems pretty good for the price. I had problems with it blowing the fuse on start-up, it seems 13A may not be quite enough. I have worked around this problem by using some 15A fuse wire instead of the fuse - you may not be happy doing this, of course. Having done that, it does seem reluctant to start up from cold sometimes, but I get around this by holding the relief valve open for a few seconds while it gets going (has to be empty for this to work).

So, not perfect, but once it gets going it's fine.

Steve

 

[irondarren]

Unless compressors have a form of slow/soft start a 3hp compressor is 2.2kw, most motors draw at least 3x running power on start up for a second or two. so thats 6.6kw or 27.5 amps

 

[Wozzaaah]

Most of the newer 3hp ones, mine included, bypass air on startup so the motor can run up to speed before it starts pumping air into the receiver. Seems to work well, it asks for a 30A supply, I give it 13A and it's happy

 

[klaatu]

I wonder if that's what mine's supposed to do but it's not working properly. That's effectively what I have to do manually with the relief valve.

 

[Wozzaaah]

quite probably, mine hisses loudly when it's starting then quietens down after several seconds.

 

[irondarren]

By rights any compressor should have a pressure bypass value that opens, when the compressor stops, this lets out all the pressure from the pipework (from pump to tank) and it should close a short time after the compressor restarts. this is to ensure on starting a compressor isnt trying to move compressed air in the pum and pipework, which would put to much strain on a motor at start up. One of the thngs that may need replacing with age is the non-return valve which is on the tank, this stops pressure bleeding back into the pipework from the tank

 

[rtbcomp]

By rights any compressor should have a pressure bypass value that opens, when the compressor stops, this lets out all the pressure from the pipework (from pump to tank) and it should close a short time after the compressor restarts. this is to ensure on starting a compressor isnt trying to move compressed air in the pum and pipework, which would put to much strain on a motor at start up. One of the thngs that may need replacing with age is the non-return valve which is on the tank, this stops pressure bleeding back into the pipework from the tank

Yes, that's how it works. My SE16C150 has a seperate bypass on the pipe between the pump & tank, on some compressors this function is performed by the dump valve in the pressure switch.