thanks to all. problem now solved.
Using a small bank of relays (plc unit was prob not worth paying for) we have now set a system that works ok. The pump needed to be switched over by manually reversing the polarity like bob explained. This was achieved by the way we wired it.
page 2 of this link shows the hydraulic unit that im on about. And the electronic board within enclosure that has been so problematic. http://www.ecssecurity.co.uk/pdf/info/FAAC%20620%20TRAFFIC%20BARRIER.pdf [Broken]
the motor is continually changing direction for the up or down movement of the barrier. After Don asking, i double checked this. The motor has a pre-wired flex to it with 3 cores and earth. As it is single phase, i presumed it must be two switch wires and a neutral? is my logic wrong...
I have been given the task to sort out a broken barrier at the entrance to my work. It is a simple enough system, push button to go up/down and a stop button. Within the barrier mechanism is 2 pistons (one for up, one for down) which are controlled by a hydraulic pump. The pump has a...
sorry, to clarify properly;
the question is three part.
a) i am given an area of SHEET material with dimensions 10mm x 20mm with rho=10`3ohm/m. i have to calculate the thickness required to give a resistance of 5kohms.
l =0.01 x 0.02 x (5000/10`3)...
leakage resistance of capacitor theory help??
i have worked out the answer to my question, yet it seems silly so have convinced myself its wrong. Please help, or tell me if i'm being stupid if you can??
a parallel plate capacitor Er=12, length=10mm, width=5mm, C=100pF...