I assume it is PT100 not PTC because temperature is measured continual (in degrees) not just as overtemperature signal like PTC do it.
Milovan Milosevic
I don't have a nameplate photo. It's a normal DC motor somewhere about 5 MW. As Gunnar said this sliprings are only for temperature measurement. Temperature element is most probably PT100. I decided that I will most probably use some converter Hz (kHz) to 4...20 mA signal. I saw that Murr...
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 ...
If you connect load like davidbeach said yes it will be autotransformer.
But as I understood original question was what will be with output voltage (two terminals bellow). My answer was in this direction that this bridge will not change anything with output voltage.
Milovan Milosevic
This bridge between primary and secondary winding will not efect secondary voltage value.
Secondary voltage will be Us = 460 * Ns / Np.
Ns - number of turns on secondary winding
Np - number of turns on primary winding
Why connection like this is used I don't know.
This is not typical...
Check one by one channel of encoder by using only one channel for feedback (via parameters setting). Attach drawings of this part, encoder type and parameters file.
Milovan Milosevic
Skogsgurra,
Thanks for response.
Of course if you dont have field there is no braking.
You can make some connection to archieve self excitation (connecting armature over some voltage divider to field) but efect of braking will not be so good because voltage on armature will drop with speed...
Drivesrock,
Thanks for response.
Partly you are right. High speed DC breaker is used during regeneration in case of network failure. But breaker or contactor on AC side will not help in this case because short circuit is formed in drive between plus and minus. This phenomana is called...
plangete,
You can read ABB electrical installation handbook, part 2, protection of feeders:
http://www02.abb.com/global/dkabb/dkabb501.nsf/0/8a84de769b6145bdc1257937003efe87/$file/H%C3%A5ndbog+-+elektriske+installationer+1SDC010002D0206.pdf
Milovan Milosevic
electrolitic,
11.75 means 11h 45 minutes
0.25 means 12h 15 minutes
0.75 means 12h 45 minutes
on phasor diagram representig as clock (12h is zero degree)
Milovan Milosevic
iop95,
Thanks for response. Dynamic breaking will be used very seldom. I am planing to control Q1 from drive so this mean that drive is switching-off Q1 after he disable both bridges (current fall to zero).
Milovan Milosevic
eeprom,
Thanks for reply.
I think in this case it is not neccessary to implement OL protection for resistor.
In our case we have 4 motors like this one. This is cold rolling mill application. 2 motors are for stand and another 2 are for coiler and uncoiler.
It is important that in case of...
One additional information: There is no possibility that load speed up the drive during dynamic braking and cause some overvoltage on drive terminals.
Milovan Milosevic
Hello all,
In attach you can find standard (recomended) circuit diagram of DC drive with dynamic braking.
Drive is ABB DCS800, 4Q, 3300A, 690VAC
Motor is 700 VDC, 2300A, 225 rpm, separate excitation.
Dynamic breaking will be used in case of drive or network failure so question is:
I DONT...
electricpete,
It will be great if you can explain from where you get this approximation:
"The negative sequence as fraction of positive sequence can be roughly estimate from "unbalance" defined as max deviation from average over average".
Thanks in advance,
Milovan Milosevic
