What Is True-RMS And Why Is It So Important?
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- Опубликовано: 24 авг 2013
- bit.ly/2IIogkQ
So what is True-RMS and why is it important to us? RMS is the Root Mean Square, or effective heating value of any ac voltage or current waveform. RMS is the equivalent DC heating value of an AC waveform.
A true-rms device is one of three tools that can measure alternating current (ac) or ac voltage:
1. True-rms digital multimeters (or clamp meter)
2. Average-responding digital multimeter (or clamp meter)
3. Oscilloscope
Only the first two are commonly used, and both can accurately measure standard (pure ac) sinusoidal waveforms.
With an average responding meter, it takes the average of a signal, multiplies it by 1.11 and displays the RMS. This only works for linear loads or perfect sinusoidal waves. If an average responding meter were to measure an electronic load such as drives or simple lighting controls, the average responding meter will give you inaccurate readings distorted by harmonics.
Distorted waveforms or non-sinusoidal waves are caused by non-linear loads, which include virtually electrons loads. Hence why a true-rms digital multimeter or true-rms clamp meter is widely preferred because only they can accurately measure both pure waves and the more complex non-sinusoidal waves. Waveforms can be distorted by nonlinear loads such as variable speed drives or computers. An averaging meter attempting to measure distorted waves can be up to 40% low or 10% high in its calculations.
Successfully troubleshooting electrical problems relies equally on good tech manuals from the manufacturer and a high quality, true-rms test tool.
Fluke True-RMS tools: bit.ly/2JD3a8Z
More on True-RMS: bit.ly/2IIogkQ
#TrueRMS #TrueRMSmultimeter #fluke289 #WhatisRMS
This is an excellent teaching video. I am in the Hvac field and I have worked with people that have told me that true RMS is not important. I never knew how important it really is for trouble shooting. I was watching videos because I am about to invest in a new amp meter. This definitely helped my decision. To all the workers out there we must know our trade.
Wow. Outstanding Video. Simple and no bullshit introduction. Just the pure information. Thanks a lot
Thanks very much for explaining that. I now have a better understanding of True RMS.
Great informative piece there...thanks .
I would love to own one of you're multimeters one day...
A very prestige & reassuring accurate device in today's world, were as the Gentleman said , how advanced & technology has evolved so fast.
With electric vehicles as an example.
You're all over the car with a meter, tracing issues... accurate reading,is essential.
Fine Meter Indeed.
Exelent video, tks FLUKE 🎩
Enough said. Thank you!
شرح ممتاز بارك الله بكم
my fluke 179 is true RMS is I have a square wave with 7℅ of duty cycle what equation can I use? Thanks for that video!
nice info..should hook it up to a scr volts/amps circuit ... thanks...:)
Question: do True RMS meter need the DVA adapter for checking pick up coils?
Hi Willy - The TRMS meter would need to have a peak function like the 87V and would not need a DVA adapter.
Today I objectively tested my Fluke 117 "true RMS" meter against an oscilloscope measurement of RMS voltage at 60 Hz, using a square wave input from a signal generator with or without offset, varying duty cycles. I would have thought that the Fluke would do pretty well. Not so, compared to the scope! When it didn't perform well at 15kHz, I assumed it was because the sample rate was too slow, but even at a slow 60 Hz it can't keep up. Presumably the refresh and higher sample rate of the scope was the difference. At 50% duty cycle it is close, but for outside limits like less than 30% duty and more than 70% the result was pathetic.
spelunkerd I’m trying to figure out how the current peak changed when he used the dimmer switch, I thought only increasing the load (reducing impedance) would result in increased current.
Hi Scott - I decided to answer this question on your original comment. Please feel free to send a reply to our answer if you have more questions!
Perfectly explained
Thanks for watching!
Great explanation. Now it's easy to justify the investment in a True-RMS metre.
Thanks for your feedback, Lynda!
I am new on electricity, and I like to have good tools, so I bought the 87V-MAX, do you guys have like a play list videos for this multimeter
We have quite a few videos that might be of interest. Check these out: bit.ly/3eBQTmq
@@fluke thank you
If my multimeter is reading continuety on the mineral resources but not beeping, what does it mean?
Hi Samson - Our multimeters will have a specified resistance value at which the continuity is guaranteed to beep and give an audible tone. That value can vary depending on which meter you are using. Which multimeter are you using and what resistance value are you measuring? Example would be the Fluke 179, the continuity beeper is only specified for ohm measurements at 25 ohms or less. Any measurements above 25 ohms is not guaranteed to beep.
how u make scope show real current,,,, pls show us setup connections
Hello - Please review RUclips link: bit.ly/2WMz0ZB This will show how to measure current with a Scopemeter and current clamp. Which Fluke Scopemeter are you using and with what current probe?
okay so how do i apply this? or in other words what does this tell me?
A true RMS meter gives more accurate results by accurately examining a sine wave compared to an averaging meter, which gives a rough estimate. The average meter is alright for perfect sine waves, but when you have distorted waves, you can get incorrect readings, which could interfere with troubleshooting or diagnostics. When it comes to sensitive electronics, it's important to have accurate measurements.
Very nice! But I'm color blind? 1:44
A is red. B is blue
@@Jack_The_Biker kind of...
Q: WHEN is a NON-TRUE RMS VOLT meter, a better choice than a TRUE RMS meter??
A: Automotive alternator D.C. VOLTAGE OUTPUT measuring. Why? Alternator output should have only D.C., without any A.C. waveform, (called DIRTY D.C.), riding on top of the D.C. If an alternator diode set is bad, the dirty D.C. will NOT ALLOW a NON-TRUE-RMS voltmeter to SETTLE DOWN. The voltage display number will be erratic. BUT, a TRUE RMS meter, set to D.C. will settle down and FOOL YOU into thinking ALL IS GOOD, when in fact, the alternator is BAD.
Applying this to music
How does a dimmer switch increase the peak to peak current? Makes no sense
Hi Scott - This would depend on the direction of the dimmer switch. If you were to dim the lights you would be increasing the resistance giving you a lower current through the bulb. And the opposite would be to brighten the bulb where you would decrease the resistance and increase the current.
Thanks sir...so true rms is for AC readings only..
Hi Abhay - A true-RMS device (RMS = root mean square) is one of three tools that can measure alternating current (ac) or ac voltage:
bit.ly/38hpMYj
@@fluke You didn't answer the question.
@@immeohmyoh the answer is yes and to be fair that link really gives more than enough info to fully answer.
@@isaacturner199 The answer is NO. A DC PWM signal from a microcontroller would also be wrong.
🙏🙏🙏🙏🙏🙏🙏
Very good sir
Ok. So then I wonder why ALL Fluke meters wouldn’t be mandatory true RMS?
O
Ask them what RMS IS.
I use fluke because it says I’m a professional and not playing games
If “True RMS” is so important, WHY do you guys sell meters without it in 2023+ ??