Lightning strike, well pump box failed

[WinterDeere]

It seems odd to me that a typical cap start induction motor would have a duty cycle well below 100%... I still have these motors, some are as old as the 1940s. Come to think of it, the only motors that tended to run hot were some cheap Asian made motors.

If you want to talk vintage American motors, you're talking to the right guyI Long before tractors were a hobby, I was pretty serious into collecting antique woodworking machinery. I had a lot of old motors from 1911 - 1948, and 2 - 5 hp in single phase, and all of them had some combination of maximum run time (e.g. 1 hour), duty cycle, or a "not to exceed temperature" rating for continuous use.

Since you like vintage American motors, here are three of those examples from my shop, a 3hp from 1948 (DeWalt), a 5 hp from 1911 (Century), and a 3 hp Wagner from probably 1920's or 30's (1934?). The temperature ratings put the onus of duty cycle management on the operator or system designer, as this will vary with application.

The only thing that failed in cap start motors would be the bearings and the mechanical start switch.

The thing that almost always fails on cap start motors, by maybe ten to one over any other component, is the starting capacitor. The 1948 motor shown above has been thru three start cap's in 20 years, but it's slinging an awful big and heavy circular blade, and has inrush current around 60 amps at 220V on start-up.

I also had several motors that were not cap start but were instead the typical single phase motor that used a start winding only, without the cap, and these also were kept running all day without overheating.

It's technically possible to start a single-phase induction motor on a start winding with no capacitor, by making the start winding out of a much lighter wire gauge, to give it more resistance than the run winding. This will cause a slight phase shift between the windings, but it would be horribly inefficient and also prone to burning up the start winding if the start relay ever failed to disengage. Bad design.

What you probably saw was actually an RI motor, which is what both of the older motors above are (note "Type RS" on Century label). These are expensive and less common, as they have a commutator like a DC or Universal motor which is switched in during the startup period, and then usually switched out once the motor is up to some fraction of synchronous speed. Despite their high cost and higher maintenance, they're preferred over cap start motors for applications with very high inertial loads, like bandsaws, because they have absolutely massive start-up torque. These would be the most common single-phase motor under 10 hp to lack a starting capacitor.

These motors would only get hot if they were stopped and started many times. But even they never got too hot, just hotter than old American made motors.

It really has nothing to do with where they're made, but how they're designed. Rockwell made more absolutely junk motors in America, than most other countries in the world have ever produced, whereas Toshiba (Japan) and WEG (Brazil) have made some of the world's best industrial motors. I've always been partial to the vintage motors from Century or Westinghouse, but that's as much for their styling and pinache, as anything else.

But since you like vintage American motors, here's one that might suit your fancy. I picked this up to run my prior table saw, which could swing a 22" diameter blade. The saw weighed 1800 lb. without accessories, something like 2500 lb. with accessories and motor, the motor alone weighed 400#.

 

[WinterDeere]

The pressure gauge read 28 psi so took top off of the 30-50 switch and adjusted it up a bit. Then using 5/16" nut driver went to close relay contacts and did some welding.

Glad I'm not the only one here who's had that electrifying experience. In my case, it was a pair of pliers, because the well pump switch was in the basement of the house and my nut drivers were way out in the shop (carriage barn). It was maybe 25 years ago, but I still have those pliers, and smile every time I see the hole I melted into the side of one jaw. Not an experience anyone is likely to repeat.

 

[Fuddyduddy1952]

This fan is old. When my physician grandfather opened his office almost a century ago he wanted a fan so he bought this used...so it's quite old. Hunter brand. Weird mechanism to change blade flow there's a lever on the side that changes blade angle.
It's in my garage and hanging on hook almost killed me! I'm betting it's 110v before 120v and runs great. 3 speed.

 

[steve tym]

Fuddy, I'm worried about a 5 second run time. Something is wrong, and it's real bad for the system. Pumps like to run.

 

[Carl_NH]

Fuddy - I agree with Steve TYM comments - 5 seconds is way to short of a cycle. When I re-read your post on checking the ballast tank you said pressure was a "bit high". Was the tank fully drained 0 PSI?

Usually when you change the switch to 40-60 in your case, you want 38 PSI in the ballast tank when empty. If you have a 20 gallon tank like this https://www.lowes.com/pd/A-O-Smith-...9h8N6PxZrRDkTlmlF64aAscREALw_wcB&gclsrc=aw.ds you will get about 5 gallons drawdown at 40-60 setting.

That should be at least 30 seconds pump run time with no water being drawn.

 

[Valveman]

Almost every component of the system has a limited number of on/off cycles. Long run times are great for well pumps. BUT, they have to be moving water. The motor manufacturer wants 1/4 of a foot per second of water flow past the motor to keep it cool.

That 1/4 or 1/2 fps (depending on motor size) is to keep motors loaded up to maximum service factor horse power cool. That doesn't change when using a VFD as it creates a smaller motor from a large one. But the motor still needs cooling flow the same as the smaller motor running at full service factor load.

However, when using a Cycle Stop Valve the drop in amps causes the motor load to be de-rated. A motor running at full speed but drawing low amperage is de-rated enough to safely pump hot water. So, it takes much less than 1/4 or 1/2 fps flow to keep a motor cool when being controlled by a Cycle Stop Valve.

I am helping a guy with a 100HP currently on a VFD. Factory says the minimum flow to cool the VFD controlled 100HP motor is 110 GPM. The VFD is set to vary the flow rated from 110 to 2000 GPM. Problems arise when trying to use less than 110 GPM. Switching to a Cycle Stop Valve the minimum cooling flow will be 8 GPM. Because the CSV de-rates the motor load instead of creating a smaller motor from a large one, the CSV can vary the flow from 8 GPM to 2000 GPM. Any flow less than 8 GPM can easily be handled by a small pressure tank. The problems of using less than 110 GPM go away when using a CSV. Working at much lower flow rates than a VFD is just one of many things that pump manufacturers hate about the Cycle Stop Valve.

 

[Fuddyduddy1952]

Answer last two posts: yes I made sure ballast tank pressure is ok. Pump is submerged in at least 10 ft of (56°F?) water so shouldn't overheat. Everything seems working fine and not sure how to make it run longer without spending lots of money.
If we open two valves it runs a few seconds...off for (guessing) 1-2 minutes and repeat. Today it's more pressure and volume it seems since I worked on it.
I'm guessing a smaller submersible pump would run longer.
I didn't check fully drained 0 psi tank pressure

 

[Valveman]

Answer last two posts: yes I made sure ballast tank pressure is ok. Pump is submerged in at least 10 ft of (56°F?) water so shouldn't overheat. Everything seems working fine and not sure how to make it run longer without spending lots of money.
If we open two valves it runs a few seconds...off for (guessing) 1-2 minutes and repeat. Today it's more pressure and volume it seems since I worked on it.
I'm guessing a smaller submersible pump would run longer.
I didn't check fully drained 0 psi tank pressure

A 20 gallon pressure tank should hold 5 gallons of water. When you checked and the air charge pressure was high, that is because the diaphragm is broken and there is water on the air side. Replacing that tank will only get you back to a 15-30 second run time, which isn't long enough. Your pump is working on borrowed time cycling every few seconds like that.

Instead of just replacing the tank, which isn't large enough to limit the cycling, you could add a PK1A and solve the cycling problem once and for all.

 

[Carl_NH]

Answer last two posts: yes I made sure ballast tank pressure is ok. Pump is submerged in at least 10 ft of (56°F?) water so shouldn't overheat. Everything seems working fine and not sure how to make it run longer without spending lots of money.
If we open two valves it runs a few seconds...off for (guessing) 1-2 minutes and repeat. Today it's more pressure and volume it seems since I worked on it.
I'm guessing a smaller submersible pump would run longer.
I didn't check fully drained 0 psi tank pressure

You may have a burst bladder tank, but first turn off the pump, drain/empty the tank to zero on pump guage, and check the bladder tank pressure - it should be 38 PSI empty. Then add air to the schrader valve on the top of the tank it should hold pressure at 38PSI with the tank drain valve open. If it doesn't, and air comes out your drain valve you have a burst bladder- Time to replace the tank. You can go to a setup valveman suggests, or go for a larger tank with 10 gal drawdown (42 gal tank or so) to minimize the cycling.

 

[ponytug]

It seems odd to me that a typical cap start induction motor would have a duty cycle well below 100%. In my machine shop I had several cap start motors that would run all day and never overheat. The only thing that failed in cap start motors would be the bearings and the mechanical start switch. In fact, the start switches would fail well before the bearings, and these failures happened on motors that were frequently started. But drill presses that were on all day never overheated. I would say that's pretty much 100% duty cycle, being on all day. I also had several motors that were not cap start but were instead the typical single phase motor that used a start winding only, without the cap, and these also were kept running all day without overheating. These motors would only get hot if they were stopped and started many times. I still have these motors, some are as old as the 1940s. Come to think of it, the only motors that tended to run hot were some cheap Asian made motors. But even they never got too hot, just hotter than old American made motors.
Eric

If you want to talk vintage American motors, you're talking to the right guyI Long before tractors were a hobby, I was pretty serious into collecting antique woodworking machinery. I had a lot of old motors from 1911 - 1948, and 2 - 5 hp in single phase, and all of them had some combination of maximum run time (e.g. 1 hour), duty cycle, or a "not to exceed temperature" rating for continuous use.

Since you like vintage American motors, here are three of those examples from my shop, a 3hp from 1948 (DeWalt), a 5 hp from 1911 (Century), and a 3 hp Wagner from probably 1920's or 30's (1934?). The temperature ratings put the onus of duty cycle management on the operator or system designer, as this will vary with application.

View attachment 3318005 View attachment 3318007 View attachment 3318021


The thing that almost always fails on cap start motors, by maybe ten to one over any other component, is the starting capacitor. The 1948 motor shown above has been thru three start cap's in 20 years, but it's slinging an awful big and heavy circular blade, and has inrush current around 60 amps at 220V on start-up.


It's technically possible to start a single-phase induction motor on a start winding with no capacitor, by making the start winding out of a much lighter wire gauge, to give it more resistance than the run winding. This will cause a slight phase shift between the windings, but it would be horribly inefficient and also prone to burning up the start winding if the start relay ever failed to disengage. Bad design.

What you probably saw was actually an RI motor, which is what both of the older motors above are (note "Type RS" on Century label). These are expensive and less common, as they have a commutator like a DC or Universal motor which is switched in during the startup period, and then usually switched out once the motor is up to some fraction of synchronous speed. Despite their high cost and higher maintenance, they're preferred over cap start motors for applications with very high inertial loads, like bandsaws, because they have absolutely massive start-up torque. These would be the most common single-phase motor under 10 hp to lack a starting capacitor.


It really has nothing to do with where they're made, but how they're designed. Rockwell made more absolutely junk motors in America, than most other countries in the world have ever produced, whereas Toshiba (Japan) and WEG (Brazil) have made some of the world's best industrial motors. I've always been partial to the vintage motors from Century or Westinghouse, but that's as much for their styling and pinache, as anything else.

But since you like vintage American motors, here's one that might suit your fancy. I picked this up to run my prior table saw, which could swing a 22" diameter blade. The saw weighed 1800 lb. without accessories, something like 2500 lb. with accessories and motor, the motor alone weighed 400#.

View attachment 3318008 View attachment 3318009

Like @WinterDeere, I have a fondness for older machinery. I do think that the comment he wrote about temperature dictating duty cycle is spot on.

To unpack that a bit, these days different motors are designed with different grades of insulation, and different temperature ratings. E.g.

There is a bit of a quirk to the NEMA motor ratings in that different intended uses have different service factors (allowed time at maximum current draw). This differs from international norms (IEC). (Full review here for the curious.) However, nearly every modern motor of typical HP that I have seen is at least 100% service factors/duty cycle. Whether the motor will last at 100% is a different call, and gets into the use, and environmental conditions.

Side note: inverter rated motors have higher insulation levels, and often design elements such as square wire, non-random windings, different rotor construction, to function efficiently at frequencies other than 60Hz. (Or 50Hz) Speaking of efficiency, there are also grades of efficiency in motors, and if the motors is in frequent / constant operation, moving to a premium efficiency motor will save energy, and often a short ROI on the added cost.

Back to well pumps; on any given well, one wants to size the pump smaller than the drawn down to keep the pump from running dry, and then large enough to service the expected consumption in a reasonable time period, but short cycling a pump is not desirable which is why there are storage tanks, but neither is a low flow long run, as the submersible pumps need the cooling as @steve tym pointed out, but also due to energy consumption. If you have a pump running against some restriction, like a partially open valve, that is wasted work and energy.

In my experience, pump lifetime gets into usage hours, how it is used, water quality, and especially the presence of foreign matter, e.g. sand, in the water. A pump that gets slowly sandblasted is not going to have a long life time.

All the best, Peter