Transformer Effect

?

Are you running electrical current through the winch cable? Is it insulated? If the answer to either is, "no," then the answer you seek is, "no."

The transformer effect is when the magnetic flux of the cable wires interact with the cable. (At the same place - auto or self inductance)

Assuming your cable is getting wound on a drum, and also assuming it is a 3 phase cable (with neutral), the fluxes of each phase will cancel each other, so that the magnetic flux leaking out of it will be almost zero (theoritically exactly zero)

In this case whether it is wound or kept straight may not matter much.

But unbalanced phases (2 phase, single phase etc) it will have the transformer effect (or high inductance) that you may have to compensate.

But then why choke? I would have expected a capacitor somewhere.

simple answer..... No!

Shouldn't if the phases are in balance. Not sure? Take temperature readings on the drum; if it's warming up, you have a transformer.

having read this again. the burning question is why? are you trying to kill your self or someone else? Safety issue are what... ignored??

and any answer you get should tell you its NOT a good idea, never mind if phases a balanced etc. buy a transformer and be safe, failing that, which church yard do I send flowers

I don't think (And sincerely don't hope) that he is using the cable as the winch rope or vice versa.

During the travel of the head, the drive cable some times are provided a drum so that the lengths don't hang down.

I think you are implying that your motors function properly when the cable is unwound, but not when the cable is wound. If that is the case, could you provide a descriptin the problem?

The chokes you have been advised to use are for dampening down harmonics which can be a problem on variable speed drives, however there should be no problem with the winch drum as previous posters said.

As for running a cable connector through blocks they would have to be very large to avoid damaging the connector especially with 350 Mt of cable hanging down somewhere. Also what about wrapping them round a winch drum presumably you will have a support cable to go with it how is this going to lay in with the electric cable.

Normally this would be a purpose designed umbilical cable with no joints and self supporting a very expensive item unless there are some off the shelf umbilicals available.

Cheers Guys

Let me start by saying that safety is not a problem with this type of cable. it is made from polyurethane outer and has a kevlar inner, which is made to take high loads of line pull. It's used through out the offshore industry because of the quality so there is no possibility of electric shocks. When in use it will carry about 16 amps with all phases in balance. The winch that will be used has a radius of 600mm so the bend radius for the cable is well within the manufacturer specifications . Like I mentioned before the control unit will be the first time this type of equipment has been used with it just so there is more controll over the speed. It will have a short duty cycle so the motors and the cable shouldn't have to much of a problem from heat. I will get some spec on the cable just to see if you can give any more information on this subject.

Bully

Anyway your question is answered- electrically no effect.

mechanical and safety aspects ?

You will have a temperature build up in the cable if running your motors at full load with large amount of coils on the drum, you might have to de rate the cable and could end up with not enough current capacity to put full load on your motors.

I found out today that the cable has a flash point of 4000 volts. Also it is used to run very high voltage and current equipment such as deep tow fish and boomer plates for deep sea survey. I have done some calculations for the size of the winch drum size needed for the length of cable. a= number of layers required on drum,b= diameter of drum barrel and c= width between the flanges. so a=200mm b=500mm and c=700m. L=(A+B)x A x C divide by K which is a constant developed for rope. so 700x200x700=98,000,000 divided by 326000= 300 meters. The manufacturer said a drum of 500mm would be fine, this will save money on fabrication and power requirements. after reading all of your comments I am happy the cable will run with out any problems. Total load should be 24 amps not 16 as i said before. 9600 watts, 400 volts. 9600/400=24 amps.

Bully

Back again. the actual amps will be 18 not 24. I forgot to add in the power factor.

You said 3 phase Then what is 9600/400 ?

The current will be 9600/400√3pf = 17.3A (assuming a pf of 0.8)

The motors are 9600 watts combined and 400 volts

P=√3VICosΦ for 3 phase (balanced) system.

= VI CosΦ for single phase.

P = 9600W

V=400 V

CosΦ known/ assuming 0.8

Unknown: I

You will have a voltage drop of about 40 Volts at 9.6 Kw trying to attain lull load with this length of cable.