Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old August 8th 20, 09:40 PM posted to sci.electronics.repair
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Default Solid state relay questions

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

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Old August 9th 20, 03:42 AM posted to sci.electronics.repair
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Default Solid state relay questions

wrote:

========================

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


** 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




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Old August 10th 20, 03:21 AM posted to sci.electronics.repair
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Default 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 established problems with established (and reliable) solutions such that the requester of such information may be relieved of taking responsibility to do the right thing in the first place.

Peter WIeck
Melrose Park, PA
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Old August 10th 20, 03:26 AM posted to sci.electronics.repair
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Default Solid state relay questions

Line drop. Bull****. 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-d...es=8&x=68&y=10
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Old August 10th 20, 05:09 PM posted to sci.electronics.repair
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Default Solid state relay questions

On 8/8/2020 12:40 PM, wrote:
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

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


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Old August 10th 20, 06:39 PM posted to sci.electronics.repair
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Default Solid state relay questions

On Mon, 10 Aug 2020 08:09:59 -0700, Paul Drahn
wrote:

On 8/8/2020 12:40 PM, wrote:
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

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

The house has a generator for when the power goes out. The shop does
not. This is why the change in power source.
Eric
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Old August 10th 20, 06:47 PM posted to sci.electronics.repair
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Default Solid state relay questions

On Sun, 9 Aug 2020 18:26:52 -0700 (PDT), "
wrote:

Line drop. Bull****. 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-d...es=8&x=68&y=10

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
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Old August 10th 20, 07:01 PM posted to sci.electronics.repair
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Default 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 issues, and they tend to fail at the worst possible time under the worst possible 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_scal...0527_front.jpg

https://images.homedepot-static.com/...g7-64_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 get stuttered power? Such as when a transfer switch kicks in and out? Nothing solid-state likes to be short-cycled unless designed specifically for that. 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 schlepping out to the shop in a howling windstorm you will bless that decision.

Peter Wieck
Melrose Park, PA
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Old August 10th 20, 07:51 PM posted to sci.electronics.repair
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Default Solid state relay questions

On Mon, 10 Aug 2020 10:01:12 -0700 (PDT), "
wrote:

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 issues, and they tend to fail at the worst possible time under the worst possible 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_scal...0527_front.jpg

https://images.homedepot-static.com/...g7-64_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 get stuttered power? Such as when a transfer switch kicks in and out? Nothing solid-state likes to be short-cycled unless designed specifically for that. 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 schlepping out to the shop in a howling windstorm you will bless that decision.

Peter Wieck
Melrose Park, PA

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
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Old August 10th 20, 08:20 PM posted to sci.electronics.repair
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Default Solid state relay questions

Could you please
explain why a relay controlled by a remote switch is a bad idea? BTW,
thanks for the links.


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 choose (it's only money).
b) A definite-purpose contactor _IS_ designed to turn motors on and off, as needed and as often as needed.
c) A definite-purpose contactor _MAY_ be designed against any number of coil 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-correct 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 same has, at some point in the last 130 years or so, been addressed and managed. Most, quite elegantly. Reinventing a simple wheel only for the sake of that reinvention is always futile, often silly, and all too often, dangerous.

Peter Wieck
Melrose Park, PA


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