Calling any swamp cooler experts

[Terryl]

OK kids, a new one on me, I have a swamp cooler down in the shop, last week it started to act up, it would run OK on high mode for about 5 min, then go into about 3/4 speed, (somewhere between high and low speed) I looked at the AC current and voltage, when it's running right it's 5.1 amps on low (motor and pump) and right on 10.1 amps on high, AC voltage is around 117 VAC, when it acts up on high it goes to 8.2 amps, AC voltage drops about 4 volts.

I replaced the motor, still the same problem, I replaced the wiring to the motor, (12 gauge solid) same problem, I replaced the switch, same problem, I replaced the pillow bearings on both sides and used good oil, same problem.

I checked the new motor, when this happens the motor is quite warm to hot, now.......WHAT the heck is going on?????????? This unit has run fine for about 8 years, now this pops up......It's about 100 degrees F in the shade so I need this running.

I have replaced almost every component in the system except the wire to the motor from the internal electrical box.

Any one?

 

[jeallen01]

Low refrigerant levels in the cooling loop, as often happens when your car aircon loses refrigerant, maybe?

 

[Lazarus]

^^^^^^^^^

+1 for refrigerant loss.

 

[John]

Intermittent supply frequency to the motor control ??

 

[Terryl]

It's a swamp cooler, the only refrigerant is water dripping down what looks like a straw mat, a fan draws air through the wet mat, and this cools the air down by about 20 degrees F, makes it a bit humid, but the humidity is about 5% right now, so it's welcome.

It has a three stage switch, low-fan/cool, and high-fan/cool and pump only, pump only is used to wet the straw mats down before setting to low or high cool.

AC supply has been checked, the connecting cord to the cooler was only rated at 15 amps, I thought it could be a problem so I pulled in a new 20 amp service, no change, supply frequecy is right on at 60 Hz.

 

[Channel Hopper]

Picture please.

 

[2cvbloke]

How do you cool a swamp, and why do you need to? Keeping the cold-blooded residents cool?

 

[Lazarus]

We don't have swamps in England.



Well, apart from Birmingham.

 

[Channel Hopper]

We don't have swamps in England.

Well, apart from Birmingham.

HOC / HOL

 

[2cvbloke]

HOC / HOL

Nah, thems are shitholes...

 

[Terryl]

Here are some photos of swamp coolers. (not the one I have...Too hot to go outside)

 

[2cvbloke]

Well in that case, when replacing stuff, did you replace the motor capacitor? When they go bad they can do all kinds of odd things, often ending up shorting out so they act like a resistive load across the motor thus slowing it down, increasing the power usage and on a fun day, going bang...

 

[Topper]

I recognise that as a desert cooler, very common in the Middle East in the 60s and 70s before aircon became affordable.
Ah you have just said that you checked the new motor. What was the power rating in KW of the old motor compared to the new motor. The biggest issue with single phase motors is that when they get replaced, people tend to replace say a 0.25KW with a 0.37KW motor assuming they are doing the right thing and building in some redundancy.
Wrong!!!, always replace with the same or even sometimes with smaller as many engineers over engineer their systems. 2cvbloke is correct. The capacitor on a single phase motor is designed for each size of motor. If the motor is overspecified for the application and the actual required output in KW is less than 80% of the KW rating of the motor, the capacitor overheats which causes a downward spiralling effect on the power output of the motor, causing it to eventually burn out the windings unless of course thermistors are fitted, of which there are single blow or bimetallic reset variety. I suggest you check the equipment specs at manufacture and take it from there.