Armature Temperature Measurement on DC motor
Armature Temperature Measurement on DC motor
(OP)
Hello guys,
Is anybody saw this kind of armature temperature measurement on DC motor (see attached photo).
We should upgrade drive for this motor with new one, and hopefully we should keep temperature measurement.
Anybody has idea what this resistance frequency converter is doing here ?
Is anybody saw this kind of armature temperature measurement on DC motor (see attached photo).
We should upgrade drive for this motor with new one, and hopefully we should keep temperature measurement.
Anybody has idea what this resistance frequency converter is doing here ?
Milovan Milosevic





RE: Armature Temperature Measurement on DC motor
RE: Armature Temperature Measurement on DC motor
This would eliminate the sliprings.
RE: Armature Temperature Measurement on DC motor
But I must supply this trasmitter somehow. Also I would not like to install anything on rotor.
Milovan Milosevic
RE: Armature Temperature Measurement on DC motor
For sure it was technology that Noah threw off the ark, maybe...but would it or a more modern adaptation of the same thing do the job?
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Armature Temperature Measurement on DC motor
Muthu
www.edison.co.in
RE: Armature Temperature Measurement on DC motor
The fact that the voltage divided by the current in the above application also measured the slip ring resistance, which might not be consistent, in series with the field rotor resistance was either compensated for or ignored, I was never sure which.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Armature Temperature Measurement on DC motor
To measure surface temperature with an IR thermometer could work. But, given the carbon dust, it will not be a very safe method.
Energy harvesting in a DC armature must be trivial. And simple short-range telemetry is yours for the asking...
But if you do nut want to add anything to the rotor, the solution you already have is as good as anything else,
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Armature Temperature Measurement on DC motor
Skogsgurra has explained the reason for converting the temperature to a frequency signal.
If the present installation is contained on the armature it may be difficult to duplicate it without installing anything on the armature.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Armature Temperature Measurement on DC motor
Milovan Milosevic
RE: Armature Temperature Measurement on DC motor
There are temperature sensors embedded in the armature.
There is a transducer which converts the temperature signals to a frequency signal.
As the temperature varies, so the resistance of the temperature sensors varies and so the frequency varies.
The frequency signal is not affected by the possibly varying and possibly non-linear resistance of the slip ring and brush arrangement.
The frequency is displayed in a meter marked in temperature.
Possibly the sgnal is sent to an alarm relay which responds to a changing frequency.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Armature Temperature Measurement on DC motor
I do not now what is tip of motor because slip rings and DC motor are different stories .
Looking at power connection assume that this is Siemens equipment where are three PTC resistors and 2 are not in operation.
Maybe pictures of nameplate DC motors and frequency converters should help in analysis .
Good luck !
RE: Armature Temperature Measurement on DC motor
The differential transformer secondaries create a "Ghost Channel" (remember old telephone lines?) where the AC components cancel and the frequency information can be read between the transformer secondaries (the now famous A and B connections).
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Armature Temperature Measurement on DC motor
Milovan Milosevic
RE: Armature Temperature Measurement on DC motor
RE: Armature Temperature Measurement on DC motor
http://www.farsens.com/wp-content/uploads/2016/09/...
I was involved with several generators using a similar technology, that seemed to work quite well.
This article discusses another system in hydro generators,
http://www.hydroworld.com/articles/print/volume-17...
I have used systems from this company for wireless monitoring of engine bearings, not generator rotors, although I'm told they also supply systems for that.
https://www.isa.org/WorkArea/DownloadAsset.aspx?id...
MikeL.
RE: Armature Temperature Measurement on DC motor
Muthu
www.edison.co.in
RE: Armature Temperature Measurement on DC motor
The only slip rings that would work in this application (and with a direct connection to a Pt100 are mercury ones. And they were banned many years ago.
BTW, the symbol (a plus sign and a Theta) stands for a device with a positive tempco - PTC or Pt100 or whatever. So we don't know about that either.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Armature Temperature Measurement on DC motor
Milovan Milosevic
RE: Armature Temperature Measurement on DC motor
There are still liquid metal slip-rings available. They use a gallium (?) alloy which is liquid at room temperature. It is expensive! We used it in the electrode assembly of a seam welder which passed current through rotating electrodes to attach a hermetic lid to a Kovar enclosure for thick film hybrids.
RE: Armature Temperature Measurement on DC motor
There's sometimes a need for such a device. Can you remember who makes/sells it?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Armature Temperature Measurement on DC motor
From a quick look on Google: http://www.mercotac.com/ for new products.
RE: Armature Temperature Measurement on DC motor
Gunnar - All this electronics stuff is way above my pay grade.
Muthu
www.edison.co.in
RE: Armature Temperature Measurement on DC motor
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Armature Temperature Measurement on DC motor
Could be! Maybe we were really handling mercury in 1996, even though we were told it was a safer replacement. The stuff we removed from the electrode was thick and lumpy, while the fresh material looked very like mercury.
I have no knowledge of Mercotac's products - that was from Google - so if it's snake oil then you have my apologies!