*sigh* another compressor wiring questions

[cdnjeepin]

I have searched the forums a few times and searched the web numerous times and am now more confused then ever.

Here is the situation:

Bought a building that has a 5hp, 230v, 3ph compressor in it, was 2 years old when we moved in. (basically this compressor but a bit older - http://oemproamtools.com/rkcomp/ic580.htm)

We don't use the compressor at work so I am gonna take it home.

Now I found a 5hp 230v single phase motor with a capacitor start on it for a great price so I bought that.

This is where I am confused..some say I still need a starter, others say I just need a on/off breaker box for it.

I am not sure what I need.

Pressure switch on it is:

Furnas
69HAIZI
on 45psi off at 175psi

Switch says its good for 3hp on 240v single. but according to the compressor maker they told me this:

"No reason you can not use the pressure switch already on the unit
It is only used to engage the mag starter which starts the electric motor
Only one contact on each side of the pressure switch is used."


We have a square D starter at work that the compressor was on, but its only good up to 3hp on 230v single also. Part #CL2510

What is the proper way to hook this up? If I can run it just the capacitor and an on/off breaker box is that safe? I am assuming I will need a 5hp pressure switch?

If I go with a starter does the motor having a capacitor on it affect anything?

So confused

 

[ddrewyor]

You will need a magnetic starter for this. The pressure switch is to carry a smaller current that trips the magnetic starter. If the magnetic starter you have for the 3hp has three inputs and outputs it can be used on a three phase motor. You will need find the current draw of the motor and the current carrying capability of the contacts in the magnetic starter. If the motor draws less or equal to the contacts current rating, you are good to go. If the motor draws a bit more, it will work, but the life of the contactor will be shortened.
If your Square D contactor has only two inputs and outputs, you will need to find another contactor. Also, some magnetic starters have an overload adjustment, that will need to be adjusted or the heaters replaced for the correct current rating if you can use the old one.
When I swapped out the motor on my compressor (went from three phase to single), my contactor had an adjustment for overload protection. The motor actually draws a bit more than the overload rating, but it has never popped and it tests out fine.
The capacitor start on the new motor will not affect anything.
Eaton compressors run a Condor switch without a magnetic starter on compressors up to 5hp. Don't know how well they work or for how long.

Good luck

Dave
________
Vaporizer manufacturer

 

[cdnjeepin]

The Square D starter that was on the compressor here at the shop has 3 inputs and 3 outputs, which I am assuming was because it was on 230V 3 phase.

So I should be able to use this starter now, even tho its going to be used on a single phase 230v system?

The contactor inside the box has this on it:

Size M1
CL2510 - Type MC03

HP max single phase 3hp
HP max 3 phase 7.5hp

 

[W-Cummins]

So I should be able to use this starter now, even tho its going to be used on a single phase 230v system?

The contactor inside the box has this on it:

Size M1
CL2510 - Type MC03

HP max single phase 3hp
HP max 3 phase 7.5hp

What do you think?? Does it say 5hp max single phase??? Of course you CAN do any thing you want to....

William...

 

[cdnjeepin]

Well I think no, but the post above made it sound like i "could" use it which confused me more.

 

[W-Cummins]

Well I think no, but the post above made it sound like i "could" use it which confused me more.

That's because you COULD use it... You could also wire your house with 20 gauge speaker wire.. I would not recommend either The manufacture put that rating on it for a reason. Will it work for some time probably, will it last a normal # of cycles probably not, could it burst in flames the first time you use it not likely, but you never know. I do know that you can get a correctly sized starter cheap off e-bay. A Used A&B 509 starter will most likely have 10 life times (yours) of use left in it and only cost a few $$

William....

[Edit]

So I grabbed the A&B book off the floor
Your starter is probably a NEMA #1 and those are rated for (at least the A&B is) 27 amps continuous output max 3hp. They list a 1p size, but I have never seen one, that is rated 5hp single phase 230v. The next common size is a #2 and is good for up to a 7.5hp single phase 230v. So it looks like the #1 is just to the low side of what you would need to have it rated for 5hp.
Also the #2 are a larger starter and seem to be going from $10-50 on e-bay right now...

 

[ddrewyor]

For some reason I thought you were going to a 3phase. So my comment:
"If your Square D contactor has only two inputs and outputs, you will need to find another contactor"
is incorrect. However, you could possibly still use the contactor depending on the current draw of the motor. Typically, a 5hp motor will draw between 22-24 amps at 220v depending on the motor's efficiency. Some motors are called 5hp and only draw 15 amps. They have a weird frame size -56 frame and are only equal to a 3hp motor. These are nicknamed "cheater 5s" because they were advertised as 5hp motors. You should check the current draw of the motor compared to the current carrying ability of the contactor.
I agree with W-Cummins that if it is a true 5hp motor, then don't do it. It won't last long anyway before you have an issue.

Dave
________
Life Saber

 

[cdnjeepin]

Thanks guys, it is a true 5hp motor.

The only mag starter I saw on ebay was the Siemens WS5-2301p, I am sure there are lot of others.

So now at least I have the compressor, motor, pressure switch, and just need to find a mag starter for it..then I can get my electrician in to wire it up.

 

[Aceman]

Thanks guys, it is a true 5hp motor.

The only mag starter I saw on ebay was the Siemens WS5-2301p, I am sure there are lot of others.

So now at least I have the compressor, motor, pressure switch, and just need to find a mag starter for it..then I can get my electrician in to wire it up.

Just tell your electrician to bring a starter for a 5HP motor. People really don't save as much money as they think buying their own parts. I CANNOT count the number of times people have bought the wrong parts and I spend more time standing around waiting for them to run and get the right ones OR I have to come back at a later date OR I end up buying them myself anyways.

 

[cdnjeepin]

Just tell your electrician to bring a starter for a 5HP motor. People really don't save as much money as they think buying their own parts. I CANNOT count the number of times people have bought the wrong parts and I spend more time standing around waiting for them to run and get the right ones OR I have to come back at a later date OR I end up buying them myself anyways.

I can certainly buy cheaper then my electrician can, I buy wholesale through our business, Just gotta make sure I get the right starter for the compressor..

Bought lots of mag starters for 3ph submersible pumps, since thats our business

 

[cdnjeepin]

Well its 6 weeks delivery for the starter I need from my local supplier.

I was looking at the starter that was on the system and its ampere rating is 27A, my motor specs are:

SF 1.15
Amps - 23
5hp
230v
3520rpm

Would it be safe to use that starter until my new one comes in?

 

[ddrewyor]

It will work for awhile - longevity depends on how many starts, loading (does compressor have an unloader), and start up current draw.

Dave
________
Gs450l