I chose Windows because Rockwell chose windows. In fact I think it is one of the Rockwell packages that is grabbing the port. The other package is also written by someone else to control their product.
Hotrod, thanks for the tip. If I get access to the guys computer that actually has...
I am trying to communicate with some control devices using the serial port on a laptop running Win2000. I get an error message which says the problem is some other program is already in control of the serial port. Does anyone know of a program which can be run that will tell me what program is...
I would like to thank you both for all your input.
In Mathcad2000 the recalc feature is under the "Math" selection. There is "Autocalc", which is turned on. "Calc" (also performed by hitting F9) and "Calculate worksheet". Auto Calc and F9 give the save results. They do not update the...
After thinking about my last post, I thought I would graph the function. Sure enough, the graph changes but the table stays at the same values. Bug or Feature??
Yes, it is turned on. Other equations change when I change other variables. Just not that particular column. It may be changing in the background but not in the view.
I have the following defined:
Min:=100 Max:=500
X:= Min,Min+50 .. Max
F(X):=X
F(X)=
This gives me a table from 100 to 500 in steps of 50, the problem I am having is if I change the 100 to say, 50 F(X) is not recalculated. It is set to recalculate. If I go to the F(X)= statement and...
What do you mean by going from speed control to voltage control. If this is a drive, I would have expected you to go from speed control (i.e. jog or thread) to Torque control. You do not mention any tension sensing device, so that is how I would expect this machine to run. And why do you list...
Testtech,
Just in case you are not aware of this, if one Scr is open or not firing, for example, you will not be missing 1 pulse on a 3phase, 6 pulse system. You will, in fact, be missing two consecutive pulses.
Edison, the fluctuations in both current and voltage are highly unusual, even if the pulses are misfiring. Is the field weaking loop tuned properly? Noise on the tach, as mentioned by buzzmoore could be a contributing factor. Monitor the output of the speed regulator with a scope. I assume it...
There is a very simple way to do this, especially if you have a PLC. Just use a loop where, when you want the linear part of the curve, you step the speed reference a fixed amount. For the S part, you increase the reference is small amounts until it reachs the step size of the linear value. At...
If you followed the manual and used the actual data it would be hard to believe you did it incorrectly. But then you should know if you followed it.
I am surprized you didn't say you auto-tuned it. Was auto-tuning available?
Lastly, didn't you record the current/torque it was running 1)...
When the chopper voltage is high, you putting current into the motor. When it is low, neglecting your relatively fast time constant, you are putting in zero current. This creates an average current. Your motor spins at a rate where the torque created by the average current = the load torque...
I have never seen a drawbridge drive but I don't see why you cannot use an AC drive for this. You have to make sure all the safety interlocks are in place. More importantly, when lowering the bridge, the drive will most likely be regenerating and it may be doing this rather heavily. This...
Wow, what is your ambient? I realize its the same for both but that is a big difference. What happens if you run the motor at 1200RPM? Does it cool down? It is fan cooled so you are losing some cooling at 1000.
What frequency is the carrier set for? And what currents are you getting now...
time = ((wk2 in ft-lb)*the change in rpm)/(308 * Tq in ft-lb)
here wk2 and rpm are at the motor. I assume you actually want to stop a load so you would have to reflect the wk2 of the load through the gear to the motor. So you actually have the gear wk2 and the load wk2. To reflect the wk2 of...
I tried a search for the JC P66 controller but found nothing. I believe it is either a phasing issue or a common issue. You would have to have a diagram of the circuit if you are going to try to figure this out.
Phasing problems were common with old DC drives. In first reading I assumed...
The voltage is changing much more rapidly than the motor can follow it. The motor is averaging the chopped voltage.
The voltage that creates current is the voltage above the CEMF of the motor. This is because the actual current in the motor is as I said above (Vsource-Cemf)/Ra. This...
The way I interpret what you said is the first supply from a separate source was a DC supply, but the second source you used was a 24 volt AC signal supplied by a step down transformer.
Was the first supply an AC supply or DC supply?
Even if the first supply was AC there could be issues...
For starters Torque is proportional to armature current but the speed is proportional to armtature voltage, NOT current.
The current the motor actually sees is (Vsupply - Cemf)/ armature resistance. In your case it is a chopped voltage supply (I assume).
The motor has losses...
You never said what the "Device" was that you were connecting to your AC and DC supply, so this may be a mute point. However, the power in an AC circuit is determined by the Impedance of the load. So unless you have a purely resistive load, your measurements may be off.
