Solid state relay questions

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   My water comes from a well. When the well was drilled I had only
built my shop and so the well is now powered by my shop. The pressure
tank and switch is also at the shop.
   Now that the house is built I need to power the well from the
house. This is fine but I am not gonna move the pressure tank and the
pump switch must be at the tank for proper operation.
   The problem I must address is how to use the switch at the tank
while using power from the house. I cannot run power from the house to
the tank and then to the well pump because the voltage drop would be
too great due to the much longer run of wire.
   My plan is to instead use the existing wires coming from the shop
and going to the well to just carry switching power, not pump power. I
want to use a couple solid state relays, one for each leg of the 240
power, to switch the power to the well. There is plenty of room to
mount two solid state relays inside the well junction box. And I found
AC controlled solid state relays that use 80 to 280 volts AC  for
control and will switch up to 480 volts AC at 25 amps. My well pump is
a 2 HP pump that draws less than 10 amps.  It is a capacitor start
type pump so it draws less current at start up than a non-capacitor
type pump.
   So, my questions: Are solid state relays suitable for this type of
work? Are they typically able to handle surge current loads from motor
starting? Here is a link to the relay in question:
https://www.mpja.com/download/33984-86RLData.pdf
Thanks,
Eric

Re: Solid state relay questions
snipped-for-privacy@whidbey.com wrote:

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** That is a no brand, triac based SSR.  

Nice and cheap - right ?  

Triacs cannot take over current surges that last more than a cycle or two.  

Why use 2 in series ? I can only see that causing problems.




....   Phil





Re: Solid state relay questions
This is water for your house. That means that it is a critical function.  

Cut the crap about what you 'can' or 'cannot' do. It is only money, and you
 owe it to yourself and any (possibly unfortunate) family as may also need  
reliable water on rare occasion. Start over, do it right and sleep well. Do
 anything else, and be prepared for the worst possible scenario.  

Keep in mind that this forum exists so that the uninformed may provide the  
least appropriate, most complicated, least reliable solutions for establish
ed problems with established (and reliable) solutions such that the request
er of such information may be relieved of taking responsibility to do the r
ight thing in the first place.

Peter WIeck
Melrose Park, PA

Re: Solid state relay questions
Line drop.  Bullshit. Use #6 copper UF cable, and the line-drop for a 400-foot run is 2.53 volts at 8 amps (1920 watts).  

Repeat: cut the BS and do it right.  

Peter WIeck  
Melrose Park, PA  

https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=1.296&voltage24%0&phase=ac&noofconductor=1&distance40%0&distanceunit=feet&amperes=8&x68%&y10%

Re: Solid state relay questions
On Sun, 9 Aug 2020 18:26:52 -0700 (PDT), " snipped-for-privacy@aol.com"

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    Pete-I already have the wire in the ground. It is sized correctly
for the length of the runs. I am not going to dig more ditches. And
what is wrong with using the existing switch to control a relay
instead of the pump directly? Would it be dangerous? Not meet code?
Would a different relay be better?  
Eric

Re: Solid state relay questions
The below was in the can when your next message came through. There are any
 number of bad reasons to do it the way you suggest. Relays have their issu
es, and they tend to fail at the worst possible time under the worst possib
le conditions. I understand that you are not in downtown Seattle, nor even  
close to it, so surety and/or redundancy is a big concern. So, if you must  
use a relay-switch, use one rated for short-cycling and for heavy currents.
 Also known as a Definite-Purpose Contactor-Switch.  

https://assets.alliedelec.com/c_scale,w_600,f_auto,q_auto,d_no_image.png/70
060527_front.jpg  

https://images.homedepot-static.com/productImages/c772b9e9-9e09-4724-aaf6-9
ae10e28a64d/svn/noark-motor-controls-ex9ck30b20g7-64_1000.jpg  

Of many, many options. This will let you control a 240 VAC line from a 120  
VAC line. The activator coil options are many, from 12V to 240V. One bit of
 advice - DO NOT cheap out on these parts.  

Peter Wieck
Melrose Park, PA  


___________________________________________________________________________
_______________________________________
And you do understand what happens to SS (any, actually) relays when they g
et stuttered power? Such as when a transfer switch kicks in and out?  Nothi
ng solid-state likes to be short-cycled unless designed specifically for th
at. And even mechanical relays wear heavily if short-cycled.  

Repeat: Bite the proverbial bullet, run a new heavy-gauge line to the well  
system, and be done with it. The first time you do not have to go schleppin
g out to the shop in a howling windstorm you will bless that decision.

Peter Wieck
Melrose Park, PA  

Re: Solid state relay questions
On Mon, 10 Aug 2020 10:01:12 -0700 (PDT), " snipped-for-privacy@aol.com"

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I'm not gonna cheap out on components. And I'm not gonna run 400 feet
minimum of #6 wire. Nor am I gonna dig more ditches in my finished
yard. I am gonna have an extra relay in the control box, just like I
have an extra pressure switch at the pressure tank. Could you please
explain why a relay controlled by a remote switch is a bad idea? BTW,
thanks for the links. I have decided to not use solid state devices
but instead will use a sealed realy.
Eric

Re: Solid state relay questions
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a)  Because a relay is _NOT_ typically rated for motor-start loads.
b)  Because a relay is not designed for the purpose you suggest.  
c)  Because a relay does not accept abuse very well.  

Whereas:
a)  A definite-purpose contactor _IS_  rated for whatever motor load you ch
oose (it's only money).
b)  A definite-purpose contactor _IS_ designed to turn motors on and off, a
s needed and as often as needed.  
c)  A definite-purpose contactor  _MAY_ be designed against any number of c
oil voltages.  
d)  A definite-purpose contactor _IS_ quite reliable if installed correctly
.  
e)  A definite-purpose contactor will take a great deal of abuse. In point  
of fact, they were developed for exactly the sort of scenario you suggest.
  

Again - this venue may often get used as a means to avoid the safe-and-corr
ect solution in preference for the Kluge solution - but that does not make  
that solution correct, nor safe, nor reasonable.  

Keep in mind that any problem with electricity, motors, and controls for sa
me has, at some point in the last 130 years or so, been addressed and manag
ed. Most, quite elegantly. Reinventing a simple wheel only for the sake of  
that reinvention is always futile, often silly, and all too often, dangerou
s.  

Peter Wieck
Melrose Park, PA

Re: Solid state relay questions
On Mon, 10 Aug 2020 11:20:54 -0700 (PDT), " snipped-for-privacy@aol.com"

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I guess I should have said contactor, which is just a special type of
relay.  
Eric

Re: Solid state relay questions
Much as a Ducati or a Triumph or a BMW is a special sort of Scooter.  

Peter Wieck
Melrose Park, PA  

Re: Solid state relay questions
On 10/08/2020 21:34, snipped-for-privacy@aol.com wrote:
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https://en.wikipedia.org/wiki/Contactor

--  
Adrian C

Re: Solid state relay questions
On Sunday, August 9, 2020 at 9:26:55 PM UTC-4, snipped-for-privacy@aol.com wrote:
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Or use a boost transformer to compensate for the drop, but only to power the pump.


Re: Solid state relay questions
On 8/8/2020 12:40 PM, snipped-for-privacy@whidbey.com wrote:
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MY well is powered from the shop line as well as your well. The  
shop/garage is on a separate 100 amp line from the service point. The  
house is a 200 amp line from the same service point.

Why do you need to change the source of service to the pump?

Paul

Re: Solid state relay questions
wrote:

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The house has a generator for when the power goes out. The shop does
not. This is why the change in power source.
Eric

Re: Solid state relay questions
On Saturday, August 8, 2020 at 3:40:57 PM UTC-4, snipped-for-privacy@whidbey.com wrote:
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Why isn't the switch at the pump? How are you going to get power from the house to the pump, without new a new power line?

Re: Solid state relay questions
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After all this confusion - I expect that the OP means to "control" the pump from the house. If I can interpret the issue (risky, always).  
a) The house has a back-up generator.  
b) The line to the pump is from the house, but the power to the tank is from the shop, not backed up.
c) The pressure switch is at the tank.  

I interpret this to mean that a 120V pressure-switch is controlling a 240V pump, powered by two different sources. Which is flat-out nuts.

I am interpreting (again, risky) that the OP wants the controls at the pump.  

So, the 120V source at the shop will control a 240V (hopefully) contactor at the pump.

All the while forgetting that if there is a power-failure, that 120V source will be dead - so, no water.  

Clue 1: The tank does not care where it is in the system.
Clue 2: The tank will be perfectly happy staying where it is, with all controls, pressure-switch, contactor and so forth at the pump - in suitable enclosures, of course.  

Peter Wieck
Melrose Park, PA  


Re: Solid state relay questions
On Thu, 13 Aug 2020 05:52:00 -0700 (PDT), " snipped-for-privacy@aol.com"

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   The tank and pressure switch are at the shop and have been so for
over 20 years. The pressure switch has two contacts. The 240 volt
power from the shop, where the tank and pressure switch are, is
switched by the pressure switch. The pressure switch has a completely
mechanical action. The pressure switch switches both legs of the 240
volt power.    
   When the house was built and I was digging ditches I put conduit in
the ground from the house to the well so that I could eventually power
the well from the house.
   Now that I have the generator panel and transfer switch installed
and bought off at the house I want to power the well from the house so
that the generator will be able to power the well when the power goes
out.
   I pulled wire from the house to the well to supply power, so now
power from the house is at the well head.
   The pressure switch must be located at the pressure tank for proper
operation.  
   I am not going to move the pressure tank.
   So all I want to do is to use the existing pressure switch to
switch the  power to a contactor coil. The power for the contactor
coil that the pressure switch will be switching will be coming from
the house. The contactor will be switching the power coming from the
house. There will no longer be any power coming from the shop. Nowhere
did I say any switch was 120 volts. What is wrong with doing this?
Eric

Re: Solid state relay questions
On Thursday, August 13, 2020 at 12:00:47 PM UTC-4, snipped-for-privacy@whidbey.com wrote:
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I have never seen one installed that way. Why not just put the pressure switch at the house, if you insist on not locating it at the pump? That would eliminate all of the jury rigged crap that wouldn't pass an inspection.

Re: Solid state relay questions
Comments:

1. use a definite purpose contactor.

2. the pressure switch might have a minimum load, so if those contacts are used to switch a relay coil, they may fail.

Re: Solid state relay questions
On Friday, August 14, 2020 at 9:38:59 AM UTC-4, Ron D. wrote:
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http://store.flw.com/content/100608/43609/ashcroft-b-series-pressure-switch.pdf

I also think that putting the pressure switch next to the well-head is a good idea. The tank really does not care where it is in the system.  

Peter Wieck
Melrose Park, PA  

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