If you are looking for something you can grow into, you might want to consider Opto22's programmable automation controllers (PAC). They may cost less than even the NI system you are considering, run on dedicated hardware, and avoid the costly software licensing renewals that NI and others will...
Referring back to the OP, if the jack screw catalog is specifying 2.75 kW at 1500 RPM, and you are planning to operate more slowly, then the power requirement will scale down with speed, with maybe a little non-linearity due to speed based friction/lubrication changes in the jack. So yes, as...
With my hardware, the quickest average cycle time I've been able to get for capturing the speed and torque is around 3.8 ms. I logged at least 30 sec of running under the conditions I described above, and got the following:
Estimated speed feedback
Avg Speed = 411.81 RPM
Std Dev Speed = 1.67...
This particular drive won't do much more than collect data on min, max, and average. It can also create a histogram showing the distribution of current readings in 10% buckets, but that isn't what I'd need either. I've checked the manual, and setting the communication speed to "fast" will...
Ok, thanks for the suggestion. I had seen a few of your posts about sensor bearings in the archives when I searched this topic before posting. I had not been aware of them, but I can think of a few places where they would be a much better fit than traditional encoders. I'm definitely filing...
Ah, I think maybe I was defining speed regulation incorrectly to compare it to that chart. The same white paper defines it this way:
The speed regulating capability of any constant speed motor or adjustable speed
drive is defined as the maximum speed change as a percentage of base speed that...
Great, that's just the response I was hoping for. In terms of load inertia, the motor is 1.5 HP and the roll it is turning (through the speed reducer) is 18" in diameter and weighs about 100 lbs. The inertia is probably still high enough to wash out any improvement from the encoder, but maybe...
The question in general is:
When using a PPR to provide feedback to a VFD, is there a maximum value above which higher PPR can actually hurt?
I understand that a higher frequency signal may be more prone to error than a lower frequency signal, so that is one aspect to consider. In this...
I'm not sure the straight spherical ball joint does what the poster is looking for. If his machine is anything like the youtube video, I think a bearing assembly of some kind is called for.
Are the driven rod and driving rods collinear?
If so, I would be looking at some kind of coupling...
I've got an older speed reducer with a mounting flange sized for a 184C DC motor. I'm looking to convert this machine to AC control with a VFD + encoder, but it doesn't appear this is a common motor size. I've identified a 145TC motor that would work well for the application... is there a...
Sorry about this mispost, I misunderstood how attachments work.
Anyway, the outboard side of the same bearing pictured about is shown here.
Outboard = away from the work roll = round side of the drawn cup.
Inboard = facing the work roll = stamped side of the drawn cup.
You can see a...
Attached are a couple more pictures. I went through the last set that was pulled out and found one so worn that thehttps://www.dropbox.com/s/ee05or07nmbdh7w/Bearing%20-%20outboard.jpg
The load estimates come from load cells that I've placed at the end of the jack screw and monitored while the mill is running. Yes, the mill is capable of delivering more force than the estimates I've provided, but we are working with strip that is only 0.002" - 0.010" thick, it doesn't take...
I didn't use the exact right words to describe what I meant, but look at the "Elastic Hysteresis" section under the "Hysteresis in Mechanics" heading in the following link. If the cable is not rigid, it could be behaving like a rubber band.
http://en.wikipedia.org/wiki/Hysteresis
Thanks for the additional information on the Danfoss drive.
So yeah, "sensorless vector" can mean way to many things to really be a differentiator on its own. At this point, the Emerson (CT) Commander SK and the Yaskawa's V1000 stand out in the <$500 range, and stepping up to ABB's ACS850 with...
Mitsubishi can be added to the list of vendors that distinguish between different types of sensorless vector control. Their E500 series has "Advanced Magnetic Flux Vector Control" which is also referred to open loop flux vector in one of their product guides. The A700 series has "Real...
Thanks for the quick response!
OK, I see the Invertek drive and agree it fits this description. Their lower E2 line has "Voltage Vector" control, which is clearly not the same thing as their "Sensorless Vector", carried in the following lines:
Invertek (EU) - Optidrive P2
Bardac (US) -...
So it has been a few years since I've had to specify a VFD, and have been doing some homework to make sure I am up to date with the current technology. It seems that there is a new (to me) class of vector algorithm that has achieved better performance than what I think of as open loop vector...
