GOOD NEWS was Reporting Compressor

This is in regards to a possible upgrade of my compressor from 3 HP motor to 5 HP motor.
I called Curtis Toledo today. Gave them my pump number (ES30). To my
surprise, the service rep told me that the pump IS rated for 5 HP motors. I told him that my guess is that the person from whom I got it, repowered it for 3 HP single phase himself as part of a single phase conversion.
Anyway. This IS a 5 HP compressor that is now being driven by a 3 HP motor, so, upgrading it is a no brainer.
Its maximum RPM is listed as 945 RPM, according to Curtis Toledo.
I will check the single phase rating of its current pressure relay, I may need to upgrade to a bigger pressure switch, or install a separate contactor.
i

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Note that the pressure switch is just wired to the coil of the mag switch anyway, it carries only milliamperes. It's the mag switch itself that may need more power. Now that I'm thinking about it, when I upgraded my Quincy from 3hp to 5hp, I also changed the voltage from 440 down to 220. Both of these moves increase the current significantly. If yours was a 3hp at 220 you might be able to get away with the same mag switch.
GWE
Ignoramus17570 wrote:

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I will check my switch tonight. I thought that it was non magnetic (no coil, just air). Maybe I am completely wrong, I am going to find out for sure. I was just looking at switches today.
i
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On Thu, 21 Dec 2006 22:25:20 +0000 (UTC), Ignoramus17570

If the pressure switch goes straight to the motor, you will need to add a 2-pole dedicated-purpose contactor rated to handle 5-HP 1-Ph at the desired voltage, or a full-on magnetic starter.
The biggest compressor duty pressure switches top out at 3-HP 1-Ph, and I've never seen a 3-Ph one. (They may exist, but...)
If you are going to three phase, a magnetic starter is an Absolute MUST - they have the overload section to sense a dropped phase and shut down the motor before the Magic Smoke has a chance to escape.
And also will catch it if one of the field coils or lead wires inside the motor goes open, before the Magic Smoke Monster makes it unrepairable. Just had that happen with a customer's paint booth exhaust on Tuesday, though with a 2-HP 3-Ph motor it's cheaper to just toss the dead motor and get another. 5-HP is where rebuilding starts to make sense.
--<< Bruce >>--
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