PZEM-021 digital Volt Amp Watt meter on a Variac with 'zero' modification
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- เผยแพร่เมื่อ 19 ก.ย. 2024
- PZEM-021 digital Volt/Amp/Watt meter on a Variac - with 'zero' modification
Links to equipment shown:
www.ebay.com/it...
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Inspiration for this video came from The Guitologist :
• Pimp My Cheap Variac w...
/ @theguitologist
This is a great video. Excellent explanation.
Appreciate it, Brad. I really enjoy your channel(s), I've learned a lot from them.
Thanks to both of you techies. Brad replied to my inquiry with two videos on this topic in One-day. You don’t get that kind of service from many these days. Again, thanks.
Thanks for the video. To anyone wondering why the current meter is off following these directions it's because the neutral from the variac is hooked up directly to the outlet (at least mine was and it is in the video as well which is why the meter isn't showing zero). If you remove the neutral off the output socket and connect it to the switch where the neutral from the wall attaches it will fix it. In other words there should only be three wires hooked up to the output socket... the ground, the hot (coming through the pzem-021), and the neutral also coming through the pzem-021.
EXCELLENT presentation man! I get SO tired of "others" wanting to make something that is easy, so difficult! You did it CORRECTLY....making something easy, well, easy.
MANY THANKS!
Thanks! Appreciate the compliment!
Thank you - the wiring diagram on the back was misleading - video was a BIG HELP!!!
Glad it helped! Thanks for watching.
Just followed this and PIMPED my Variac! Great video! Although, you neglected to tell the viewers how on the factory wiring of these variacs, it's not like they made ANY attempt at a mechanical connection before they soldered. LOL! Once you put some heat to a solder joint, wires just pop right off.
Excellent video, very concise. I noticed some other people have commented about their meter "jumping" , just not going up or down smoothly. My meter does the same thing, but it doesn't really bother me, I installed this meter mainly for the other information it provides as my variac already has a digital meter. Thanks again for a fantastic vid, it made this mod a piece of cake!
Thanks for uploading this! You explained the process so that anyone with basic skills can perform the mod. It makes the meter much more useful... Take care, Tom
Thanks! That was exactly what I wanted to accomplish.
Many thanks for all this easy to follow info.. My PZEM-021 is still on it's way to me, but during the delay from ordering to it' imminent arrival, I have had the jitters on the install. Feeling very confident now and will do the mod you show to extend the low voltage readout. Coincidentally, my nickname at School (back in the 1960's) was Paladin. 😃
The mod really is that easy. Thanks for watching and commenting!
Hadn't thought about modding the meter supply, I'll be taking mine apart and adding it. Thanks!
Thanks again, following your easy directions it took about 15 min to add the meter to my Variac!!
Glad it was helpful. Thanks for watching and for your comment.
thx for the vid, that really helped solve the problem of getting down to 0v... ill cheers a glass of sweettea to that!
Awesome! It worked for me. My variac is identical to yours except it's the 5a model. Your instructions were dead on and they made the mod a piece of cake too.
Glad it helped. Thanks for watching!
To add a few steps. You must disconnect the wiper wire from the load outlet before connecting it to the display wire (the one that was heat shrinked and zip tied). Also, there is a jumper wire going from the neutral on the load plug to the variac power switch that has to be removed. Pretty sure I have the exact same variac as this one and I had to do this.
Thanks for clearing everything up. I wish I would have seen this video first. You explained it quit well, so that even the not too bright people among us can understand it. That BS about if you have to ask you probably shouldn't be doing it, is just that-BS. People need to learn from good teachers, and do things the right way. Almost anything is easy if you know how to do it.
Thanks for the view and the kind words!
I'm so happy I watched your video. I knew there was something funny about my variac the same one you have. I felt a tingle of higher voltage a couple of times. Turns out this unit wasn't wired correctly either. If it wasn't for the isolation transformer I'd probably been fried by now.
I'm getting one soon and I'm hoping they fixed these bugs.
That is brilliant - just ordered my meter. Great work sir
Many thanks!
I have a Genrad 10A Variac and I won't be drilling or modding it, but I'd sure like to incorporate something like this. I normally run the output to an isolation transformer, and a Kill-a-watt.
Thanks
For the info
I hooked up the pzew 021 to my variac with the zero mod...works like a charm
Glad it was helpful. Thanks for the comment!
Pala,, I recently found this meter and your demo. My Variac is different, but I am sure I will find similar connections and wiring inside. Thanks for explaining about how to make the meter read 0V. I will see how things go once mine arrives.
Glad you found the video useful. Good luck.
Hey paladinjme! Thanks for the helpful vid! I have the same unit as you have in your video. Followed your directions and it worked like a charm. I kicked my unit up a notch by putting the meter in a plastic enclosure and fastening that down to the Variac housing with an aluminum angle bracket and some screws. Thanks again!
Glad it helped! Thanks for your comment!
best video on this subject,,,way better then Brad's. I also ran a 340 ohm resistor from line 5 as a bleed off. Saw that bit in another video...not sure it is worth the time to install, bur didn't hurt anything. Good Vid, thanks
Thank you, appreciate it! Big fan of the Guitologist!
What size resistor? Would 1/4W be OK? What was connected to either side of the resistor? Can you reference the video that suggested adding the resistor?
wow i can not thank you enough .all the other videos kind of tell you but i am just learning electrical engineering and so i don't just wanna do thing i wanna know why to and you really answered all my questions . others would say things like go to hot lead and the neutral side but you went into detail and it helped so much .teaching would be the perfect job for you because it was a great video. yes it is really basic stuff but if you go by the meters diagram it did not work right for me. also some just used 3 wires. yours made so much since thank you so much. cant wait to see what other videos you have
Excellent !! Thanks a ton !! Curious tho - given that the "full power to the meter" mod is so simple - why wouldn't they manufacture it that way in the 1st place? Having the capability to measure clear down to 0 volts AC is so obviously very useful !!
I think that's because this meter is designed to be used within a normal range for household voltages. Just my guess.. Thanks for your question!
Thanks for a great detailed video!!
Thanks for watching and for your comment!
Just installed for my new variac (model TDGC-0.5KM), although I had an extra step. In my variac, there was a wire connecting the neutral side of the switch directly to the neutral lug on the output plug. This had to be removed. I don't see this wire in your variac @paladinjme, so I assume it's a new addition.
Very clear where one side of your capacitor connects to. Where does the other lead connect to?
The other lead on the capacitor stays where it was, on the board.
Thanks for this. Worked out great
Thanks for the view and the comment!
so you don't connect the capacitor back to the board after cutting and connecting the lead correct? Also my meter unit is PZEM-061 It should be identical installation and mod correct? I'm just double checking as I don't want to fry my meter out the box.
1) you don't connect the capacitor back to the board after cutting and connecting the lead - CORRECT.
2) my meter unit is PZEM-061 It should be identical installation and mod - I cannot answer this question, as I do not know the differences in my meter and yours.
Thank for watching!
@@paladinjme ok thank you very much. It's nice to get a response from someone here. Love the channel. 5star from this viewer.
Thanks for making this video, nice and clear presentation. I have the smaller (500VA w/ 5A fuse) version of this auto-transformer and your mod works perfectly with that model. I might run a test on one of my larger transformers at some point, I'm sure it will work. Also noticed you had ice in your drink at 1:12 and that it was all but gone by 9:00.
Very observant - I hadn't noticed that. I don't recall how long it actually took to record this video...but obviously quite a bit longer than the ~9 minutes or so it ended up being. Thanks for watching!!
Great video, I am not clear about the 5th lead , do you connect a wire to the board where the lower lead from the yellow capacitor was connected? does that mean you in fact make the capacitor disconnected? thanks.
Cut the lead from the board, solder on a wire (the orange wire in this case) connect the other end of the wire to the hot side of the fuse.
@@paladinjme Got it, thanks for your quick reply.
I got a meter that has a completely different wiring diagram and it is confusing to me. This one came with a little current ring. It has load going to 3 and 4 and it says CT to 1 and 2. How would that be wired? It shows the ac in of the load going to 4, then the what I assume is the neutral going to pin 3 from the load then the pins 1 and 2 go to CT which I assume is current? So how would you draw a diagram for that like you did with the meter you installed?
Same problem here. Send help! 😂
Thanks for the informative video. It helped a lot. Just wondering where the baseline 30mA on your meter comes from? Is it reading the amp draw from the on/off switch light?
I assume that is correct - reading the draw from the light in the switch. Thanks for watching and commenting!
The inside of my PZEM-021 looks slightly different - definitely is the PZEM-021 though, possibly a newer circuit revision? Measuring between the pins, 1+2 don't appear to have a resistor between them? Measures under 1 ohm? Will this way of wiring up the meter still work?
On my variac, the yellow lead (to the wiper) is connected directly to the left lug of the plug (looking from above). Do I disconnect from the plug, wire to the meter, and then wire out from the meter to the lug? As in, does the regulated voltage out go through the meter first, and then on to the plug? To be clear, by "plug", I mean the outlet on the variac where you plug your amp or whatever in, and NOT the main feed from the plug you stick into wall voltage.
I think the image @ 2:00 answers your question...wiper goes to pin 3 (into the meter), pin 4 goes out of meter to the hot side of plug. HTH!
I screwed up the 5th wire, please someone could explain again, what I need to know is, one end of the 5th wire is soldered to the hot side of the fuse, the other end is my problem ,do I solder it to the board or to the yellow capacitor lead? I know for you guys it all makes sense but I'm totally blank when it come to fixing this kind of stuff. anyone could chime in and make it crystal clear for me .thanks.
Solder it to the lead on the capacitor.
@@paladinjme Oh man, that was fast, and crystal clear now, a simple thank you somehow is not enough but I want you to know I sincerely appreciated your help.
Are the connections any different for a dual receptacle variac? I was not able to get it working with dual receptacle variac I purchased. Wondering if the ganged neutral wire in the ganged receptacles and the meter connected causes the variac short. When I connected as instructed in the video and tested, the meter worked for minute or two then stopped functioning. As I turned up the output of the variac it started to hum as if loaded. I assumed there was a wiring error, but I didn't find one.
You sure helped me out! Thanks!
Glad I could help!
Nice mod! What wire gauge did you use?
I believe it was 16 or 18ga stranded copper.
Wired the PZEM 021 as you did. The power display does not read correctly. Seeing 2.4W when a 40W light bulb is connected. Please help.
You're seeing 2.4W at what voltage?
@@paladinjme 120V AC
You can also order them with the dig meter now.
Super helpful video that allowed me to do the mod perfectly. The only issue I have is that when the variac switch position is “Off” the display still lights. Any ideas why that would be happening? Thank you!
interesting and i can see the usefulness of the 0v mod, however i must ask this just to be thorough will this cause an issue later? i mean for example forgetting to turn the variac off?, voltage spike/feedback? slightly inaccurate readings? just asking.
I'm not sure there is any way to predict that...but we are talking about cheap Chinese components, I'd keep expectations low.
@@paladinjme ALL electronic componants are made in china including the ones people are paying big bucks for like "sozo" caps. what i meant was is there any detrimental effect of clipping the cap from the board at one end and wiring it as in the vid vs leaving it alone and dealing with it not powering up till it sees 60ish volts.
Ok ...wiper comes off fuse goes to pin 3 and pin 5 takes it place on hot side of fuse....correct?Thanks for your reply.
It's tough to say with certainty more than I've already have, especially not having the schematic for your particular variac - which shouldn't be vastly different in principle than mine. Tuorum periculo! - Thanks for the questions!!
Awesome video. I followed it and was able to get the same meter hooked up to the same variac. One thing though is my meter is slower to respond than yours. I turn the knob and the meter doesn't change for about a half second the jumps up. It's not a smooth climb. Is this something in the wiring that I did or just the meter itself? Thanks again!
Thanks for the comments! The jumping around sounds like an issue with the meter, you could easily test by seeing if you get the same 'jumping' on a multimeter.
paladinjme OK thanks. I'll check that out. It's not so much jumping around as just a lag in the numbers changing. It does go up and down fine just very choppy, not a smooth, constant change like in your video
I checked with a multimeter and that works fine. It seems like my meter has a slow refresh, the numbers change only every second or so and not real-time. I hope that's not due to anything I did with the wiring.
Hi, My variac is wired a little different. From what can see in the video 2 neutral and 1 hot are tapped from plug and switch. The remaining wire goes to variac wiper, now my wiper wire goes to hot side of fuse,do I desolder that and solder wiper directly to pin 3 and pin5 goes to fuse taking the place of original wiper wire?Thanks ...looking forward to my mod.
Pin 5 goes to the fuse - so that is always gets 120v. Pin 3 goes to the wiper.
I have a similar meter, perhaps made by a different manufacturer. Different layout but it also has a 1uf cap. Is your 5th wire going into the circuit through the cap or bypassing the cap? Mine has a 10k resistor coming off the line input, into the cap which bypasses 2 resistors and then into a diode network. Cheers!
I believe I've answered my own question. I've added constant power to what I would call the input side of the capacitor before the diodes. Installed on my older Variac W10MT3W (with damaged meters) and works like a charm.
Indeed, I have constant power directly from the hot side of the fuse directly into the cap. Thanks for watching and commenting!
paladinjme I really appreciate you posting! Really helpful 👍🏼
Great video and I appreciate the PZEM 0V mod. However I'm about to toss the PZEM because it's very hard to read with a terrible viewing angle and dim LCD. I'm going to upgrade to a color KWS-AC300. Just curious if anyone has done the 0V mod on this display.
Thanks for the great video. Can you explain why some of these AC meters have an external coil to measure current and some do not? Is there an advantage to one over the other? Is it possible to read true current without running one lead through a coil, as my handheld clamp ammeter does? Thanks again.
I would say that the values displayed on the analog meters on this particular model are dubious, at best and are only to be regarded as 'relative reading'. At the very least, I would reconcile it again a good DMM. The only other indication of current on this variac is the topside label, which I would regard as something just short of completely useless. HTH. Thanks much for your questions!
paladinjme Thanks for the quick reply. Hope to see more on your channel!
Tried to do this mod, checked and re-checked the connections multiple times, and quite sure I have it hooked up as shown in your video. When powered up, the meter turns on, but the variac starts smoking at the wiper. What am I doing wrong? Would appreciate any advice. Thanks.
Very helpful video, thanks! The LCD on my meter remains lit, even when my variac (same model as yours) is switched off. Is it supposed to be in an “always on” state?
Sounds like your fuse may be in circuit before the switch. Mine is Power -> Switch -> Fuse. If yours is Power -> Fuse -> Switch, then just wire the '5th' wire (lead from capacitor) to the 'switched side' of your switch.
That’s exactly right, thanks so much for the quick reply! I’ll give it a try. BTW...the incoming neutral line is connected to the switch, the neutral lug on the socket, and the variac coil, all at once. Does that sound right? Don’t trust wiring in this thing. Thanks again!
@@64ES335 I have added a 1/4 amp fuse in an inline holder between the digital meter and the switched hot side. Probably not necessary, but easy to do and made it just a bit safer if something in the meter goes bad.
Hi, excellent video. I try the 0 modification on V 5.0 and it works from 0 to 170v then it shot down the meter...why?
Another video about this showed that the ground connection doesn't connect through the powder paint coating.
True or false?
Anyone?
That's certainly possible...I'd say just remove the ground, use some sandpaper to remove the paint and re-attach the ground.
paladinjme :
I will for sure.
One video showed a lot of soldered connections, another showed connections bolted to the chassis ... maybe they improved their build.
Also, I want to wire in a digital meter to get a more accurate reading.
I see a lot of videos showing an inexpensive digital meter being wired into the variac.
That sounds like a “must do” to me.
This is a stupid comment. But, is that an old Fiesta Texas mug of iced tea on your workbench? I have an identical mug here on my bench....
I actually have 4 of those identical mugs, all with different logos / designs on them - Budweiser, WWE, Super Bowl 33, and Florida State Seminoles - ...I got the first - Budweiser - one at the PX in 29 Palms, CA in 1992, bought the rest on eBay, been using them daily for 27 years. Guess I'm a creature of habit...
How do you wire the PZEM-061
Does your ammeter work ? I hooked mine up like yours and my ammeter doesn’t read past .003
What components are you using? Resistor and Capacitor please?
Just curious as to what you are asking? He isn't adding anything to, just modding the existing component to be able to read down do zero. Are you under the impression he is building from scratch?
amigo gracias por tu aporte! buenas noches! tienes el diagrama donde se muestra la modificación?
Anyone has this problem : Works until it reaches 47 v. Then Lights out, Then show 1983v 999.9a, thena s your turn the turn variac higher, it just fades out
I had inverted the Ac line on the diagram. but then it shows constantly 119 volt.
Okay, I assumed pin 1 was the top non coloured one and pin 4 the lowest coloured one. Inverted everything and well, now it works!
Hi Palidinjme, I have a question for you. I recently bought a Chinese variac model SC-5M 5amp 500 watts. My question is that I want to run this with my guitar amps to lower the voltage slightly to 118 volts. I saw a video on TH-cam where a guy showed how he had to run an additional wire connected to the chassis for a proper ground. Apparently, according to this guy, these Chinese variacs are not very reliable nor properly grounded. My amps are expensive. I would like a Staco 5 or 10 amp variac, but Digikey and two other companies sell one of these to the ludicrous price tag of $721.00 for one of their good variacs. Others are just plain ridiculous, the price and shipping. So after the fact, I went and bought one of these Chinese variacs. I then proceeded to come up with a lot of bad reviews about these variacs. Are these safe to use and do they have a UL certification certificate. Have I mistakenly bought a boat anchor? And advice? Thanks Michael Newell from Niagara Falls, Ontario, Canada
All I can really tell you is that mine works satisfactorily. I can't vouch for yours or how suitable it is for your intentions. I can state the obvious and say these are Chinese imports and thus probably of dubious quality.
gotta replace the voltmeter on mine anyway, since it arrived pushed from thge frame and i better pay some guy to do it as wont tinker that much with chinese stuff
That's a big mug of rye and coke..
Would be bourbon & Coke if it were an adult beverage, but alas, it's only tea. Thanks for watching!
SOUND U S .
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