waross described it perfectly.
I've serviced blow molding machines that were sequence controlled by type of device.
They were actually quite complex, having 20 - 30 switches, having multiple other control devices integrated into the control.
Those machines drum controllers were sequenced with...
This issue comes up with large DC motors as well. The ducting that delivers cooling air to the motor, including the brushes, is often unwittingly sealed with basic "whatever is on hand" sealants, and they can have an adverse effect on the brushes.
Bill, we are absolutely in agreement there. The rotor enmasse shouldn't be anywhere near the NF of the risers.
I mention the resonance of the entire assembly - of the motor connected to the rest of the machine, because it appeared to be missing in the conversation.
The curved elements that are...
To ignore torsional resonance is to ignore the fact that each of those "spokes" has mass, and to ignore the slenderness ratio of them. Their length compared to their stiffness is substatial. Torsional vibration will cause them to move a lot, and since they are "other than" straight, they will...
A big name VFD and motor supplier from Taiwan has had success and experience replacing large DC motors in rolling mills with VFD driven heavy duty squirrel cage motors.
They've been approaching us for our abusive application, and I've spoken with their refference, a mill maintenance manager...
Sorry Uly79 for the late reply. You are likely already beyond this problem.
Piston seals have friction against the walls.
Imagine yourself in the chimney on american ninga warrier. You can support your whole weight by spreading your legs and pushing your feet against the walls.
Most hydraulic...
On the subject of motor construction, couplings, and spring rate:http://files.engineering.com/getfile.aspx?folder=76495dcc-899e-4624-9e96-33709a361cc8&file=050927_Motor_Shaft_Spring_Rate_Study.pdf
As an asside to that... the method for calculating the spring rate of the shaft of the motor is "fuzzy" at best, particularly when dealing with large motors which have broad variations in means of construction.
In our case, attached to the other end of the drive shaft is a machine, the rotor of...
You gentlemen are way beyond me in the DC motor world but I may have some usefull feedback.
1) Whoa yeah that looks like a lot of flexing in the images for copper, which annealled or not work hardens quickly. Visually issolating just a single laminated pair based on the indications on the...
The 100 ton hydraulic load, there is likely some static friction that is not being overcome either in advance or afterwards.
The "dithering" of the rig may be is allowing settling, so that your 100 ton load becomes something slightly more due to the mass of the hydraulic rod being no longer...
Short of having a dyno:
Best way by far is the regen VFD.
For it to be accurate you MUST perform the autotuning function, otherwised you will not be able to trust the torque and power values.
The poor man's way, but still very accurate:
Build a pony brake. (Search "pony brake dynometer" on...
