Recent content by notsosmart

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. cheers guys...

page 2 of this link shows the hydraulic unit that I am 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

thanks. 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...

hi 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...

Is this simply; R= 10'14 x ((5.31x10'-5)/ 0.01x0.005) which equals 1.062x10'14 ohms?? This is the value I calculated first time but was not convinced?? Thanks for helping

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. answer; l=A(R/rho) l =0.01 x 0.02 x (5000/10`3)...

leakage resistance of capacitor theory help?? Homework Statement 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...