Long story short I moved my shop and no longer have 3 phase power. My compressor, 3 phase Keaser SK26 with an integrated KRD100 dryer, is not usable and I’m in a pickle. It’s a beast and if I did a phase converter it looks like it would end up pulling 120amps roughly. Not an option.
So. Do I get another compressor (single phase) for roughly $1200 and just run the air from that compressor into the Kaeser tank and through the air dryer or sell the Kaeser (3-4k) and buy a compressor with an air dryer roughly 5-8k as far as I can tell. 5k seems hard to find. It seems pretty simple to run air into the Kaeser tank but is there anything I’m overlooking?
You might want to look into a used military genset. They output 3 phase. depending on your location you might find it’s the cheaper solution. Especially if this is an interim shop or you are thinking of getting 3phase power ran in the future ( depending on location and power co infrastructure this is a $10K+ option just to get it to the pole. Plus the electrician to wire in a 3phase panel inside. An option for a business at some point but outside the $$$ pocket book of most of us hobby guys .).
The tank and dryer can be purchased from Keaser separately so a single phase compressor is always an option… I think I’d just think out of the box. That’s a nice bit of kit to sideline .
Have you looked into a VFD? 220 single phase input to VFD and 220 3 phase output from VFD.Dont know what hp your compressor motor is, but sure there is a VFD that would work. Just another option and a lot cheaper than buying new compressor.
I use a VFD to run my 3 phase 220 Bridgeport knee mill works great, and VFD on my belt grinder.
Would the drier not require 3ph? Any compressor you get for 1200 is not going to be much. I would be hard pressed to give up your current set up unless it has had a hard life. I agree looking for a used genset might be the way to go depending on timing
@rat196426 I thought the same thing. Then I looked up the specs on his unit. American rotary says it’s going to need 150 to 200Amps to account for the inrush of the rotary motor starting up. This keaser unit pulls almost 50A on the 3 Phase line.
Yeah. I looked into it and from what I gather is that if your machine pulls 60amps on 3 phase you need a VFD rated at 120amps as far as I can tell. This panel only has 125 amps so I’d be out of luck. A Bridgeport pulls 2hp and 5-6 amps so you can get a way with a 15-20amp 3hp VFD. It’s a whole different ball game.
How many amps does it pull? American Rotary has idler motor types that can handle that compressor. I have one in my shop that handles up to 10 hp. They make them for up to 100 hp. That is a fantastic air compressor. 3k and you will be up and running. The Idler-type phase converter is noisy, but it’s sure not as noisy as the compressor.
Interesting. I’ll look into it. I believe it pulls 60amps but that’s from memory with a 20HP motor. I’ve only got 125amps on this breaker panel to play with.
A 20 hp 3-phase motor at 3600 should be around 54 amps. That is a full load. The small service panel is an issue. Run the compressor and almost nothing else. Screw compressor will run with less load than a reciprocating compressor. Plus, screws produce less heat to hold moisture. Much easier for a refrigerated dryer unit to eliminate the moisture.
I’m with @rat196426 get a simple vfd from automationdirect. You don’t need to worry about changing the frequency or the speed just get it set where you need it and forget it
I don’t believe a VFD would be able to restart the compressor with an air-pressure load inside the tank. But I have been wrong many times before. It’s definitely a cheaper option. CLAUDE says it will work on a rotary type.
Bigdaddy, every compressor I’ve been around has an unloader circuit that bleeds the pressure off the compressor when it starts. No real sure about screw compressors but I’d be surprised if they didn’t have them too.
You need to make sure you get the correct digital phase converter to run a hard load like a air compressor. Many of them drop the manufactured leg once they start up. Then you lose 1/3 of your horsepower. Here is a video of a compressor trying to get started…. This is part of the reason I went with a rotary. https://youtube.com/shorts/3mtT0eugmDI?is=c3Ea3SSl3A56eAfh
I was honestly think the Genset gets wired directly to the air compressor. Via a fused disconnect box. That would give you the safety you need in cause things go pear-shaped but the power you need to do the job.
I wound up getting a 60 gallon 2 stage Ingersoll Rand and just running the air into the 100 gal Kaeser tank, which is integrated into the Dryer/Fridge and out from there. Works fine, just noisy and damn, the initial shutoff isn’t until 175psi so that motor is running for a while before it finally kicks off and both tanks are full.
I’ll probably put a regulator on set to 130psi right after the IR tank just so that motor will shut off sooner. 130psi is when the systems kicks back on too.
I wanted to adjust the pressure on/off but the Tech said IR hasn’t used adjustable shut off since 2009. I really like the Kaeser or maybe I should say I really don’t like these types of compressors with this motorcycle engine on it, just a racket. Not sure what I’ll do in the long run, but it’s a whole lot of compressor in here now.
Digital phase converter would not be possible in here and the thought of running a diesel generator to power my compressor is not something I wanted to get into. Just too much maintenance, keeping jugs of diesel around.
