7.5kw motor

[shurbunkin]

hey guys



ive wired in a 3 phase motor for a work shop and i think ive connected the phases right. It doesnt need a nuteral and the earth is bolted to the metal work. ive switched it on but when it starts the motor runs for about a second then stops and the breaker trips. Its got a 16amp thre phase breaker supplying it. I think it needs a 20amp. Just wanted to make sure incase i damage the equiptment.

The connections ive made are l1 to w2, l2 to u2 and l3 to v2 of the motor and have metal links between w2 and u1, u2 nd v1 and v2 to w1


cheers guys

 

[Tiny Spark]

Some pics of the connections and the rating plate would help mate.

 

[Silly Sausage]

What type of breaker is it; B, C or D?

 

[shurbunkin]

I cant seem to attach a picture. I copy the picture in and im told the url is too long.
The breaker is a 16c type breaker

 

[telectrix]

far too little info.

1.star or delta? 2. what size cable feed? 3. does starter have an overload?

answer these and we might be able to hepl.


help even

 

[telectrix]

pt pic on desktop on low res. then add image from computer.

 

[bossian]

What's the motors purpose?

 

[telectrix]

What's the motors purpose?

to go round.:smilielol5::smilielol5::smilielol5::smilielol5::smilielol5:

 

[Silly Sausage]

far too little info.

1.star or delta?

It's Delta I think, by the way his links are.

 

[telectrix]

what links?

 

[Silly Sausage]

what links?

The metal links the OP mentions in the OP!

 

[shurbunkin]

its for a power unit driving hydralic pumps. The motor rating is correct. Im wondering wether i need to put i higher breaker in

 

[shurbunkin]

taking the board cover off the cable size between the board and the comando socket is 2.5mm which seems way to small

 

[D Skelton]

Oh for god sake get an electrician in will you!

"I think I've done it right???"

Do you now?! Well my friend, if you were competent to be carrying out the work in the first place you'd know if you'd done it right!

FFS! I feel like crying sometimes!

 

[Tiny Spark]

Why do you think the 2.5 is to small?
We really need to see a rating plate.

 

[Besoeker]

its for a power unit driving hydralic pumps. The motor rating is correct. Im wondering wether i need to put i higher breaker in

The starting current for a typical cage induction motor is six to eight times FLC and will last for pretty much all of the run up time. Upwards of 80A in your case and possibly for a few seconds given that it isn't a high inertia load. Your overcurrent protection needs to reflect that.

 

[telectrix]

The metal links the OP mentions in the OP!

my mistook, thought i was looking for a diagram, but apparently he could not post one.

 

[Barry White]

Why do you think the 2.5 is to small?
We really need to see a rating plate.

/\ /\
what he says

without the rating plate we wont know anything you have wired it in delta which is "usually" the lower of the 2 voltages on the ratings plate theres a similar thread here http://www.electriciansforums.co.uk.../31498-supply-calculations-3-phase-motor.html
if it helps you showing the info needed to wire a motor. what motor protection have you fitted?

 

[Rockingit]

You've now posted this exact same thread on two (at least) places on the internet. Stop playing with things you clearly know little enough about and get someone who does know enough. There's enough of us around to at least save you the cost of a funeral.

 

[Darkwood]

Shurbunkin.... Normally Im happy to help but you are clearly dabbling in this with no experience, many questions need asking and its unlikely you'll know the answers.

-What brand is the mcb this is your first question?
-What mcb does the manufacturer recommend for DOL on a 7.5Kw motor (clue if its a hager they state either 63a(b), 50(c) or 50(d) but varies slightly from brand to brand)
-Is the circuit solely providing the motor or is it part of a larger system?
-Due to the 2.5mm been on a 50+ mcb can a fixed load clause be applied to the set up so you can over-rate the mcb to the ccc of the cable?
-If you can will your ELI still comply?
-What if any experience have you in Industrial motors and controls...If none walk away and don't take on work you are not competent in.

Other questions that effect circuit design -

Motor run up times
Incoming supply size
Frequency of start up also if a motor has inching option
Starting methods and stopping in some cases
Sorry I could go on here to cover all bases but as you have already said it for Hydraulics some of the questions need not be asked but still we need a lot of info that your not supplying.

PS ... give an insight as to why your little 16amp mcb is tripping in the scale of things and yes you may have to increase cable size to meet ELI even if the set-up is classed as fixed load and O/L protection of the cable is not necessary.... Can we assume the starter has O/L motor protection?