Hello Chaps (and ladies?!)
I'm an electronics engineer that's been offered a job as an electrical design engineer. I've been to have a look at the job and it doesn't seem too complicated however when I had a look at the CAD system they use to layout the circuits I was instantly lost, all the symbols that are used for contactors, MCB's etc are totally different to the electronics world. I borrowed a set of electrical drawings for a machine so I could study them, some things just don't make any sense to me. The first thing is the Emergency Stop relay unit PNOZ1, I've had a look at the internal diagram for this unit but it doesn't make sense (to me!), I can't seem to identify how the contact coil(s) are driven/connected-up, I can see 'K1' 'K2' and 'K3' boxes and these seem linked to sets of contacts... Another item I can't fully understand is the MCB wiring, sure the 3 phases come in, go through the MCB contacts and into the motor, no problem and logical except further along in the drawing list is a page showing showing ALL the MCB's on the machine connected in series (from a 240V supply) and ending up feeding an i/p to the PLC to indicate ALL MCB's are closed, my problem is that the MCB's don't appear to have an additional set of single pole contacts which can be used to indicate 'MCB is closed'. What am I missing guys???
I would be very, very grateful if someone could give me the benefit of their own knowledge to help me out. I've tons of questions that can only be answered by people in the know. Thanks in advance, John.
I'm an electronics engineer that's been offered a job as an electrical design engineer. I've been to have a look at the job and it doesn't seem too complicated however when I had a look at the CAD system they use to layout the circuits I was instantly lost, all the symbols that are used for contactors, MCB's etc are totally different to the electronics world. I borrowed a set of electrical drawings for a machine so I could study them, some things just don't make any sense to me. The first thing is the Emergency Stop relay unit PNOZ1, I've had a look at the internal diagram for this unit but it doesn't make sense (to me!), I can't seem to identify how the contact coil(s) are driven/connected-up, I can see 'K1' 'K2' and 'K3' boxes and these seem linked to sets of contacts... Another item I can't fully understand is the MCB wiring, sure the 3 phases come in, go through the MCB contacts and into the motor, no problem and logical except further along in the drawing list is a page showing showing ALL the MCB's on the machine connected in series (from a 240V supply) and ending up feeding an i/p to the PLC to indicate ALL MCB's are closed, my problem is that the MCB's don't appear to have an additional set of single pole contacts which can be used to indicate 'MCB is closed'. What am I missing guys???
I would be very, very grateful if someone could give me the benefit of their own knowledge to help me out. I've tons of questions that can only be answered by people in the know. Thanks in advance, John.
