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Need some Phase Angle Controller Help

edited September 2013 in Accessories

Just wanted to run a quick question by you guys, I made a phase angle controller a year or so ago and it worked perfectly, and i then added an ammeter, a plug and socket on the element side for convenience then my problem arose. Here is the components i used so you can know what i'm dealing with

UNITED AUTOMATION - PSR-25 - POWER CONTROL MODULE

HONEYWELL S&C / CLAROSTAT - 53C3250K - POTENTIOMETER, COND PLASTIC, 250KOHM, 10%, 2W

I also incorporated a 240 volt cooling fan pointed at the oversized heat sink for added safety when i built it.

So, the new plug and socket are installed on the element side, the ammeter is in-line on the uncut neutral leg coming into the box. So i fill the boiler to cover the element, plug said element into the control box, then plug control box into the wall. Then it comes on like normal! all systems go, the ammeter goes to 22 amps so i attempt to adjust the dial and then poof goes the smoke!!! No more control from the pot, it stays at 22 amps on the gauge. and the pot gets really rough to turn. Take it apart and find the pot to be toast and arcing marks from the pot to the metal box its housed in. Now does it matter if the pot is isolated or grounded? Like i said the controller when plugged in, defaults to full on, i looked over everything and cant find any touching wires or anything out of the ordinary. So before i order at least a new potentiometer i guess i need help finding out what went bad so it doesn't happen again. Any thoughts would be great!!

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Comments

  • Yes sounds like you let the magic smoke out.

    1. Your ammeter needs to be on one of the legs to the element AFTER the controller. You don't give a monkeys about the supply current, what you need to know is the LOAD current. Inline with a CT ? Is it the correct one for the voltage ?

    Both leads to the pot are live, but the body of the pot should not be. Did you touch one of the pot connections to the box?

    A sketch of your circuit diagram would help. What voltage are you on? UK 240v?

  • Pot should be 470-500k

    StillDragon North America - Your StillDragon® Distributor for North America

  • edited September 2013

    @Smaug, it says on the psr-25 that it requires a 250k ohm pot. So here's my diagram, minus the switch.

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  • Don't forget the power rating of the pot - it needs to be 2watt minimum in most cases, the greater the load capability the greater the control current. Most standard carbon pots like on a stereo won't cut the mustard.

  • Yes that looks fine. It should have been OK unless you had a defective pot.

  • @Myles said: Yes that looks fine. It should have been OK unless you had a defective pot.

    Perhaps... But like i said its worked fine for the last year and i've used it dozens of times. So when a ssr shits the bed, does it even work when plugged in?

  • Also my concern is that i have all of my controller in a metal box with a semi unintentionally insulated lid, to which the pot is mounted in. So if the mounting surface of the pot were to ground to the earth circuit could that have caused the short?

  • It should not, the case of the pot should not be connected internally to any of the three leads on the Potentiometer.

  • I have looked back at the 1st post and from your description and observation of similar situations in other applications previously, my gut reaction is this:

    When you initially applied power to the controller you already had your pot set to the maximum position. You have had a power spike (totally normal on switch on) but because your pot was set to its minimum resistance you have cooked it. Your switch on current can be many times greater than your typical maximum current.

    From that point onwards the situation is a cascade. A dead pot is not unexpected. With any of these controllers you should ensure that you have the control turned to a minimum setting when you apply power.

    The controller itself may well be fine, you just need to fit a new pot and try it.

  • @Myles, yea i generally try to make sure its at its lowest setting when plugging it in and i don't remember doing that this time.... So i believe you are right. This also explains how it acted after it popped too. It defaulted to full on, little to no resistance but then i could spin the pot to a burned or rough point ie. "open" and the amp gauge would go to zero. So two new pots are on order one just in case it does it again because it was something else. And i will report back on with my results.

  • So the new pot came in from newark, no change, didn't fix it... Installed it the same way i did before and when plugged in nothing happens. Heatsink cooling fan comes on so i know i have power to it, but any turn of the knob has no effect, amp gauge reads zero. So next stop is a new ssr... When i built this project i didn't know that still dragon existed so i used parts from another source and the ssr alone was and still is $45!! So i could buy the entire kit for SD for that price alone! My problem now is, is that i have x amount invested in pot's that only fit the ssr that i have. So i guess i need to bite my tongue and buy a matching ssr and pot from @Smaug and kick my $16 shipped pot to the side.... Rats, o well hindsight is 20/20. note to self: Always go with the Dragon!

  • So... I installed the new components, ssr and matching pot from smaug, the same way i had them installed before, make sure everything is kosher, turn knob all that way to the off position, plug in the power and the amp gauge pegs 22+ amps then pop!

    Okay at this point it has to be user error... Which i thought i covered my tracks but clearly something is touching or shorted or something... So i took everything apart, all the connectors, the element guard kit and nothing! can't see burn marks, bare wires or anything. I even took pictures so some fresh eyes can look at it. I'm at a loss, this is too simple to be giving my this many fits. The last time it shorted out was obvious, crushed a pot wire against the heat sink, fine fix that replace the parts problem solved right?
    I'll post pics as soon as i get them off my tablet. I shouldn't have to ditch the whole dang thing and start over but i'm about too....

  • edited September 2013

    So in an effort to track down the root of my problem, i bypassed the ammeter by placing both black wires on one lug, i then bypassed the ssr by putting both white wires on one lug, plugged it in then flipped the breaker, and it came on no problem. So that tells me its not in any of the plugs or connectors, i have seen the ammeter work before so that should be fine, unless for some reason it won't work with the ssr. Now, if the pot case is grounded by means of putting the threaded part through my boxes lid and threading the jamb nut on is that an issue? because the lid to my enclosure is a grounded to the green wire inherently. So that wouldn't have anything to do with it would it? Its worked before like that? The scorching on the wires is from heating the shrink wrap.

    Could i have miraculously gotten a defective ssr? I haven't said that until now due to the previous failure being my fault. Also the power comes in the box near the ammeter, and leaves through the connector. Which by the way kicks total ass, its made by Neutrik, bought it from Newark's website and its very heavy duty. I highly recommended it!

    THANKS3 15% promo code anyone? good through Oct 31st. Thought i'd share

  • edited September 2013

    im not an electricians a hole but pics may help?

  • edited September 2013

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  • Can you show a pic of the bottom of the pot and describe which one is going to 3 and which one to 4 on the ssr, they are both white. If they are incorrect you may have full power when pot is on low and might be what is causing it to blow.

  • edited September 2013

    image

    I made it match the arrangement i had on the one i got from newark in my first post.

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  • Now assuming on the pot end they are hooked up correctly, does it matter what wires go to what on the ssr? as in positions 3 and 4? all its doing is creating a resistance which isn't directional correct?

  • Looks like you are using the correct legs on the pot so it should be on low when it is turned down, not sure about the resistance part but compared to my controller the middle leg, the wire on the left in that pic is going to 3 on the ssr and the outer leg, on the right is going to 4. Is this how you have it?

  • I looked at the DIY controller thread and on page 1 Lloyd posted a nice diagram showing the middle leg of the pot going to three and the outer to 4, and a few other diagrams show the same, so I followed that and mine work fine. It also shows you can connect the unused leg to the center also, but not necessary. Hope this helps you.

  • edited September 2013

    @captainshooch said: Looks like you are using the correct legs on the pot so it should be on low when it is turned down, not sure about the resistance part but compared to my controller the middle leg, the wire on the left in that pic is going to 3 on the ssr and the outer leg, on the right is going to 4. Is this how you have it?

    I'll double check about that... That's really the only thing that's left that I can think of as far as something being wired wrong.

  • @Cambo, can you try bypassing the ammeter. Leave the SSR, pot & fan as normal in the circuit, and bolt the two black wires together. Make sure you also have some water around your element, and see if that works.

  • Will do! What are the odds that the ssr isn't shot?

  • So was it just turned on full blast when i hit the power? I had the knob turned full anti clockwise. just like the pictures of the coming soon still dragon knob stickers? I guess i don't know if the ssr goes to full output with the least resistance from the pot, or no output. If i knew that i would know if i burned it up by not having the power turned to full or to off... any thoughts?

  • Only suggestion I have is - try putting the black wires (phase???) on the SSR and the white (neutral??) thru the ammeter and see what happens.

    With ammeters the general rule is, put them in series with the phase/Hot wire. - not that it makes any difference here.

  • edited September 2013

    Do you have a multimeter? If so, unplug your controller from the power supply, turn the pot full anti-clockwise, and measure the resistance between the following:

    1. two white wires on the pot
    2. two outside terminals
    3. center terminal and unconnected terminal

    When you measure the resistance between the two white wires, and turn the pot, your resistance should change from - 0 to 250K ohms or so. Be aware that some multimeters wont measure high resistances.

  • Philter your knowledge of wiring is so admirable i would like to know just a fraction of what you know

  • Would open on the SSR potentiometer input (infinite resistance)mean 'no output' and shorting it with wire or pliers or something (0 ohms) be a quick way of testing the SSR and pot?

    FYI - With my experience with regular SSRs, you will need a load on the power side of the SSR when testing, or it will float high with leakage current and give you a false reading.

  • @cooperville said: Philter your knowledge of wiring is so admirable i would like to know just a fraction of what you know

    Thanks Coops, but being a sparky definately helps (insert flash-over emoticon). I try to help where i can
    :D

    @CothermanDistilling said: Would open on the SSR potentiometer input (infinite resistance)mean 'no output' and shorting it with wire or pliers or something (0 ohms) be a quick way of testing the SSR and pot?

    FYI - With my experience with regular SSRs, you will need a load on the power side of the SSR when testing, or it will float high with leakage current and give you a false reading.

    From what I understand, you are correct CmD. One could substitute a 60W light bulb for the element to test the SSR.

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