in a previous video in this series we looked at are direct on-line starter and we saw how we use
that to start a single phase motor and then we had a look at some variations on that theme and we're
using remote start stops and multiple stop devices indicator exactly that's right so what we're going
to be looking at in this video then Matt so this time around we're looking at the exactly the same
direct online starter but this time it's going to be operating a three-phase motor okay previously
single phase motor this time it's a three phase motor right important thing to remember is
everything remains the same even the coil is still a 230 volt coil right okay so it's a three phase
yeah but 230 volt coil sure and because it's a 230 volt coil that means we're going to
have to bring a neutral into this system yeah so the neutral won't be going through
to the motor just for that is the neutral will be the supply will need a neutral
ground to it fantastic so if we have our three lines coming in yeah we have L1 coming in to
number one contact yep L2 coming to number three and L3 coming to number five very good now again
you know perhaps one approaching this for the first time i go ah my neutral will go in there
and again we've got our three phase motor here and it simply just goes
all the way through through the the overload the overload relay
very nice straight down to our three-phase motor it's just worth noting as well on certain
manufacturers of overloads you find that these pins move don't you you can sort of move them
from one position to another depending on what uh the physical size of the contactor is when
you can throw that on the bottom so they're kind of like they click into different positions so if
you are struggling to get it in maybe that one of the pins just need to know that because with these
types of terminals you can't go directly through the center it's either left or right
okay so this in this situation everything's so much more simple there's no neutral to worry
about bringing around yeah it's just nice and nice and easy it's good okay then so we've still got
our retaining contacts numbers 13 and 14 and we need to take a phase to one of those okay
and so i always choose to take um take it from number one just my drawings
that's very standard practice i think isn't it i think some people do that yeah
and again it's a microscopic load here isn't it so it's not going to cause any issues if you've got
lots of calls connected again we've got our start button over there so in this
time we're going to come across all the way to our start here very nice and again through the
other side of the normally open contacts yep we're going to take from number 14 all the way
across to number 80 and again we're seeing what we saw before that the start button
and the auxiliary contact here the latching contact they are in parallel with each other
and so so everything's everything looks pretty much the same as how it was before
yeah and again we need to take down from number 18 down to the stop button yep and again from the
stop button all the way across to the normally closed yep terminations of 95 and 96 so this is
our overload content that's the overloaded contact okay and then again we're going from 96 back
and then i'm going to go back very nice so that's that's that's where we got before that's exactly
the same yeah so we've got our circuit going through there the only thing that's missing
is our neutral conductor and this time the neutral's got nothing to do with any of the
terminations the neutral just simply comes into just as a separate conductor there and
then into terminal A2 very nice into there very good so again we've got that circuit completed
and we've seen that same principle that we saw before if i press the start button i create a path
that the current can flow through it will flow through there and uh through there and up to A1
it's bringing that coil in which is fantastic and when the coil comes in these shoot over making a
contact not only to the motor which will then be energized but also between terminals 13 and which
means that when i take my finger off the button current can then flow back through the circuit
through the circle again fantastic just just basically bypassing the stop button that's inside
the start button so that's basically well that's basically the three-phase circuit right for a
direct online starter that's pretty cool um we'll just talk about the there's the um we spoke about
95 96 97 98 it's exactly the same you can still have an indicator yeah we won't draw it on this
one yeah but you can do it's because we've got a neutral up there so we can still have an indicator
up there the setting of the of the overload yeah that's important to know yeah because say for
example if we had a if it was a single phase um three kilowatt that would be approximately 13 amps
whereas if it's a as this is a three phase three kilowatt motor yeah it's going to be roughly just
four amps or something yeah so a third of the the uh the current on single phase load yeah very good
and if you'd like to know the reasoning behind that and the maths behind that and some of the
mathematical formulas behind that then please head over to Joe Robinson Training our science
and principles channel and you'll find there lots of information on that subject as well
okay so i think i'm quite happy with that really i think that's something that shows
again you know being three-phase it's not scary is it there's nothing more complicated about it
it's just a matter of understanding that we're going to use all the contacts for the three
phases to the motor no there's no neutral going for the motorcycle a balanced load so we don't
need a neutral in most cases and that we can see that the neutral just goes on to A2 so actually
it's almost as simple if not a little bit simpler than the single phase connection and again we
didn't talk about it last time but the there's no there's the earth connection yeah and there's an
earth connection on very good exposed metal work and we can develop as we as we would for any road
obviously are we just not showing on here for the sake of clarity and the sake of simplicity
so should we sign this one off i think so i get it right this time okay we've been practicing