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what can you tell me about 3 phase jag drives (inverters) :confused:
never had any dealings with them before and havent a clue about them.
ive applied for a job and looks like much of the work involves this type of equipment so any info would be helpful before i make a fool of myself at the interview :eek:.
cheers in advance
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  • #3
Hi monty,
any info would be great as i have never come across them before.:eek:
Been put up for the job by my father in law who has sung my praises a bit too much and i think part of the interview will be installing/setting up and probably some sort of testing:confused:



I'm just trying to find a powerpoint presentation I did last year for an assignment I did at college which covered the basics

seem to have no college file :eek: bear with me:)

right...cant find anything:eek: had problem with my laptop last month and it seems to of all been wiped:confused::(

ok will try my best to give you enough info from memory:) but it is a huge subject

I may be wrong but I assume you mean VVVF drives/inverters (never heard of Jag drives sorry)

firstly they can be connected with single phase as well as three phase supplies (tend to be smaller motors with single phase supply) this is because the first thing the inverter does is convert the AC supply to DC using a rectifier bridge.

Missing out the boring part lol (which believe me is a good thing and I think is going a little far)........the output from the inverter varies in voltage as well as frequency hence the name (variable voltage variable frequency) to maintain the torque of the motor the ratio between the two remains constant.

The speed of an AC motor is dependant on frequency and number of poles so obviously the sole purpose of the drive is to supply the motor with varying frequencies at any time for example ramping up within a set time etc.

Configuring the drives is a huge subject and quite difficult to go into, it could be set up closed or open loop (for a simple example if driving a pump could be wired to a flowmeter and could ramp up as flow decreases etc)

Now before anyone says anything I know that I havent even touched on the subject but lets face much are they expecting you to know? what are they gonna ask? I know for a fact that many on here know more than me (about everything) and Shakey for one will hopefully be along and help you properly :)

I'm gutted cus the PP presentation was really good and went into lots I have forgotten to write..if you want to know any particulars that I havent covered please ask

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  • Thread Starter Thread Starter
  • #5
Hi craig,
thanks for the help. Not sure what is expected of me when it comes to demonstrating what i know but a bit of revision is called for i think as nearly all my work is domestic/commercial and this industrial side is new to me.:eek::confused::eek:
Once again thanks for your answers.:)


Might be also worth brushing up on 4-20mA current loop stuff, as Monty says, this is very often (not always though) how inverters are controlled.

I cant imagine a firm would chuck a new bloke in at the deep end, its a good oppertunity to learn new stuff though !


Although they all work on the same priniples each manufacturer's product will be set up in slightly different ways. Usually you'll find that one manufacturer is selected for all the drives used throughout the plant. This means the maint guys only need to learn one manufacturer's set-up routines and terminology. Plus they only have to pay for one software licence as most of them now can be set up using a laptop.
If the old man knows what specific drives are used you can have a poke round the maker's website for various pdfs describing the product parameters, installing and setting requirements. At least you'll not be going in totally blind. They should in all fairness offer you an orientation to them or send you on the manufacturer's course 1 or 2 days.
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