Connect AC volt meter

[steele6707]

I have a Simpson Model 55 0-150 AC volt meter (iron vane type per the data sheet) that I wish to use to measure the 120 volt line voltage gong to a small (13 amp) electric kiln. (This will be mounted inside a digital controller box I am putting together for the kiln.) I would like to confirm that I run a wire (I plan to use 18 guage) from each terminal on the back of the meter with one going to the to the hot side and the other to the neutral side of the power cord to the kiln. I looked on the web for connection details and this looks like the way to connect, but I would like to be sure before I actually do this.

Would this also be the appropriate forum to ask questions about the PID temperature controller if I have any? I have not started to connect this yet.

Thanks

 

[LiteYear]

Suggest you get a leccy to check your wiring. Given your experience, it's too easy to get wrong over the Internet without being able to see what you're doing.

Other question sounds fine, but again, if it's a relatively simple question about wiring then people might be hesitant to offer advice that could be misinterpreted. Photos that clearly show your intention would definitely help.

 

[VEBill]

This Data sheet?

http://www.simpsonelectric.com/images/File/datasheets/round_datasheet.pdf

Exact model number: "08470" ?

You're right to double check because there are sometimes meter movements with scales calibrated for the completed instrument.

In this case, the data sheet seems pretty clear that the meter is intended to be connected directly to an input directly matching the scale. The data sheet mentions external divider networks included for the higher voltages.

But in this case, direct connection seems correct.

Beware the terminals with the direct connection to AC. They should be protected from accidental contact by humans.

Beware the 18ga wire protected (not really) by the upstream kiln circuit breaker. If there's a fault at (for example) the meter itself, what prevents those 18ga wires from glowing white hot?

Stand by in case others have more or better info.

 

[VEBill]

Correction: red hot, not white hot.

I missed that it's a small 13A kiln, not a 50A monster.

 

[steele6707]

Thanks to all for the replies. Attached is a pictorial/schematic of what I am wanting to do. I will make the wires to the volt meter 14 ga. I believe the cooling fan, alarm buzzer, and wiring into and out of the PID Controller can be 18 guage (these items all have #6 screw terminals or 20 ga leads). If anyone believes different, let me know.
I am a civil so electronics design is not my strong point, but I put together Heathkit stereos in late 60's and I am comfortable with simple house wiring and understand the dangers of line voltage.

I do appreciate your time and comments. - Don

 

[VEBill]

Residential wiring (at least in North America), Black is Line/Hot, White is Neutral, Green is ground. Your diagram uses the Red/Black colour code commonly used with low voltage DC wiring. Just beware that the Black wire is Line/Hot.

I've not (yet?) reviewed the entire diagram.

 

[steele6707]

VE1BLL - Thanks for the reply. I did not have a good way to do white lines, so I used red for the hot and black for the neutral. I am in the US (Kansas City). I forgot to let you know about the volt meter. It is the model number you listed. I am not really doing any design other than sizing the wires for the connections. All of the parts came with wiring diagrams except for the volt meter. The rectifier fuse wiring was part of the wiring diagram for the solid state relay. I also plan to fire the kiln outside on the porch. I have an old metal typewriter stand I can set the kiln and the controller box on and plan to sit with it while it fires. It takes less than 15 minutes to get to 1650 F and then the silver metal clay needs 20 minutes to sinter (or up to 120 minutes for maximum strength) at the 1650 F and an additional 120 minutes to cool down after the power is turned off. The firing chamber is 6" x 6" x 6". I am building the controller box so I can use it on this kiln and could also use it on a kiln I would build if I wanted a larger kiln.

Thank you for your comments. -Don

 

[steele6707]

Attached is a revised copy of my schematic. I tried to make the colors more consistant - I have used a heavy black line for the Hot side and a grey dashed line for the neutral. I moved the rectifier fuse to be in front of the solid state relay (I had it placed after the relay because I had misread the schematic) and I added component terminal numbers.
Thanks - Don

 

[jraef]

What are you trying to read, the output voltage of your SSR? If so, what kind of SSR output is it? Zero Cross variable time base, Phase Angle, or PWM? Depending on the answer, you may be disappointed with the results of the meter reading. Why is the voltage reading important to you?

"Will work for (the memory of) salami"

 

[steele6707]

My idea was to see the voltage going to the 13 amp kiln (which is the output of the SSR). A data sheet is attached and I have the SSRL240DG25. I expect I will see 110-120 volts on the meter for the 10 to 15 minutes for the kiln to reach 1650 F. Then the temperature controller should cycle the SSR to maintain the temp. for an additional period of time to sinter the silver and I hope to see the voltage change during those cycles. I am curious as to how long the cycles will be.
The kiln has a theromcouple tied to meter with a temperature scale. The PID temperature controller has a thermocouple that will indicate a temperature on the digital readout and will also allow the controller to turn the SSR on and off. The volt meter is an indicator that adequate voltage is going to the kiln.

Does the data sheet indicate that what I expect would be likely to happen?

Thank you for your interest. - Don

 

[jraef]

OK, so you have a simple on-off SSR, there is no voltage variation involved, it is either off or on at the full voltage of the incoming line. I don't see a need for a volt meter, it will give you no more information than a pilot light would.

"Will work for (the memory of) salami"

 

[waross]

Your results may depend on the time base of the PID output and the damping of the meter.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

jraef,

Some of these PID controllers cycle the SSR using integral cycle control (aka burst control) and use the thermal mass of the heater to act as an integrator. The voltmeter might read some intermediate value although I suspect relating it to heating output might be a bit of a leap of faith.

 

[Skogsgurra]

Scotty
I would see it as a major offence if I told a reputable and knowledgeable member that.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[ScottyUK]

Lucky it was me who did it and not you, Gunnar

jraef - no offence intended, I know that you know this stuff inside out.

 

[waross]

Has there been any specs posted in regards to the PID controller? Without some information on the controller we may be wasting our time.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[steele6707]

Thanks to everyone for their comments. The controller is sold by Automation Direct and is a SOLO SL4848VR. It may best to forget the volt meter ( I really do like the way it looks though) and use the hole in the front panel for the cooling fan. I was going to put a hole in the top for the fan. Jreaf mentioned a pilot light and I may drill a hole for one of those.

Thanks - Don