I worked on an instalation today thet had 3 415 v 16A sockets parelleled up all protected by one breaker. is this common practise? are there any safety implications? i cant see any provided that the cable sizing is adequate for the breaker
i have been asked what are the safety reasons why most three phase isolators dont break the neutral. My response was that the neutral is held to earth potential and therefore is used in testing for isolation also keeping it connected prevents the neutral from floating to a higher voltage . Are...
A dc motor at work is driving a lineshaft that drives 4 seperate levels of machinery via mechanical clutches. we have a problem at work whereby it is throwing out the clutches whilst accelerating. This is happening on a motor drive combination that has been in and running for several years so it...
Does anyone know if I should be able to interface directly with a AB panelview 550 via a 1747 pic when the panel view is not connected to anything else other than a 240v power supply .
I have bought one to have a play about with and am having trouble connecting to it?
I wish to improve the indication for which guards are open on a machine at work.
The current system includes several guards in series driving a dual loop safety relay, the safety relay then goes on to drive an ouput to a plc that indicates that there is a guard open within a specific zone of...
i am working in a printing press the uk and have been requested to make some modifications to a guarding circuit on the printing press. I have some conecrns with how i stand
legally i am sure that some of you will have come across this problem before.
the machine has evolved over many years and...
i am trying to monitor activity from a comms port on a plc with some software i have downloaded. The plc comms port is rs485 the pc is rs232. Can i just use the txd+ rxd+ to the tx rx of the PC i am not looking to analyse any data just to see that it is being transmitted.
If an output is used and switched on in a subroutine that is not called in subsequent program scans will it switch off again in the next scan or does it remain on unitil the rung that sets it is called again and changes state
cheers
I am working on a motor gearbox assembly that is fed by a small inverter. The inverter is single phase 240v input three phase 240v output 50hz.
The motor connected to it has been connected in star or wye format.
I find this strange because the motor has two conection possibliteis 415 star or...
Hi, is there a rule of thumb for the maximum amount of IR comp that can be used without risk of burning out the motor windings. i am having trouble with some 240v three phase motors that run for prolonged periods of time at freuencies as low as 3hz. They have been in service for some time and...
I am looking at a three phase inverter driven motor 7.5kw that is reported to be whining more than usual. i can hear a whine that sounds specifically like a standard inverter motor whine. However can think of no reason why the whining would have got worse. Have inspected the connections and...
i am using some software that monitors packets of data to and from the comms port of a plc and displays it in hex.
the comms port on a working system is an rs485 link with 4 nodes on one branch and 4 different nodes on another parallel branch each branch has 120ohm terminating resistors across...
Can anyone give me a brief idea of what the term frame refers to concerning PLC programming.
I believe it has something to to with the configuring of comms ports to communicate with external devices but want to know more
i am looking to replace a system that uses a dc drive to drive a dc motor gearbox assembly with an inverter driven ac system. how do i go about designing such a system. what information do i need to take from the dc arrangment before deciding on an ac replacement i am aware that it is possible...
why when i use my multimeter on diode test does a Schottky barrier diode measure only 1v in the reverse direction. forward biased it measures less than 0.2v
and it is for this low forward volt drop that i wanted to use it but was expecting it to measure o/c or 3v as is normally shown on my...
what should be my point of reference concering safety regulations when designing electrical systems. for example if i were to design a conveyor belt driven by a dc drive(this is just an example) how do i start to find out the safety reqirements that i need to design in. for this example
does the...
how can i predict the volt drop across a diode for a given current through it whilst forward biased. i ask the question because i am working with a drive that has an analogue reference that has a diode in series with it the refernce signal varies from 0-5v.h measurment i can see that the volt...
any recomendations for which type of devices i could use to totalise the flow of newsprint ink (a similar consistancy to grease). the flow rate is low maybe 1-2 l an hour on demand and zero when off demand
thanks
