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dks
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Join Date: Jul 2013
Posts: 15

AC SCR Drilling Rig

03/25/2015 2:38 AM

I have just started working on a new assignment of rig engineer in an AC SCR drilling rig (E-1400-XI). There are two Draw works (900 HP DC motor), two mud pumps (900 HP DC motor) , one rotary motor(900 HP DC motor) alongwith its auxiliaries. There are four power pack with Cat engine and a mix of Kato/BHEL alternator. One of the mud pump is not working at all...can anyone guide me to troubleshoot it ? Please , my request to this esteemed forum. (faced this problem earlier also)
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IdeaSmith
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#1

Re: AC SCR drilling rig

03/25/2015 3:04 AM

What part of the pump is not working?

More information required.

If the pump turns but does not pump will be different from it does not turn, because then it can not pump. Check if mechanics of pump are ok.

Good luck with YOUR assignment. No-one here will do your work or guide you if you do not do your work. Currently you are not telling us whats wrong.

I have a pump in the cellar which is not working, its not connected to the mains.

You see where this is going?

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dks
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Join Date: Jul 2013
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#2
In reply to #1

Re: AC SCR drilling rig

03/25/2015 3:17 AM

SIR, I mean pump is not rotating at all. it is a dc shunt motor which operates between 0-750 VDC controlled by the driller thro hand throttle. I have asked for help.... In the meantime if I have to do troubleshoot how I will proceed step by step, that is what I need to know.thanks

regards

dks
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Crabtree
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#5
In reply to #2

Re: AC SCR drilling rig

03/25/2015 6:08 AM

I'd start by isolating it and letting an Electrician loose with some test equipment, then, I'm funny that way.

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IdeaSmith
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#8
In reply to #2

Re: AC SCR drilling rig

03/26/2015 1:21 AM

You need to find out why the pump is not rotating. What have you done so far to rule out mechanical blockage on the pump? Is it an electrical fault or are we stabbing in the dark?

Where is the electrician to check the electrical side?

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JRaef
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#3

Re: AC SCR drilling rig

03/25/2015 4:32 AM

Not much to go on here. Is there an electrician there with a meter? First thing to look at is if the motor is getting power. If it is, you have a bad motor. If there is no power getting to the motor, start going backward from the motor to where that power comes from and when you get to the component that is not giving power, check the other side of it and see if IT is getting power fed to it. If it is, that's where the problem lies. You still won't know what it is, but you know WHERE the problem lies.

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Just an Engineer
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#4

Re: AC SCR drilling rig

03/25/2015 4:40 AM

Start from basics and then proceed from there.

Presuming that it worked "yesterday", then suggest the following.

Is the controller actually sending a signal? (no leads to get new controller, yes leads on.)

Is the actuator responding to that signal? (No leads to repair, yeas leads on.)

Check fuses/safety devices.

Is the power source energised?

If pump makes noises and shaft "tightens" to load, then jammed pump. If no motor response, then motor problem.

(Take these as hints and draw up your own decision tree based on what you know about the rig and how it is supposed to work.

BE SAFE!!!!! Don't open covers you don't have authorisation to examine, Don't put things in the way of anything that might move once this is sorted. REALLY bad things can happen.

Hope this isn't an initiation to the rig. Could be a simple thing like fuses removed or blanked just to put the pressure on you.

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Phys
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#9
In reply to #4

Re: AC SCR drilling rig

03/26/2015 8:14 AM

I spent 11 years in the "oil patch" running elctronic borehole devices, which failed often and became a bit of a trouble shooting expert - that's the way I'd go at it. Good answer.

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bigg
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#6

Re: AC SCR Drilling Rig

03/25/2015 11:30 AM

Are there any error codes showing on the drive display?
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GW
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#7

Re: AC SCR Drilling Rig

03/26/2015 12:18 AM

DC machines are wonderfully simple. So the deductive reasoning is straight forward.

If you power up and have current going to the motor you will produce torque IF there is field.

So check if the rated field current is flowing and the field terminal voltage is close to rated. IF SO, and you have rated or higher Armature current then the motor is most likely mechanically jammed.

IF you have rated field current and voltage, but no (or very low) armature current, then check if you have armature voltage at the terminals. If you have high voltage and no current then the motor is open. IF you have no voltage or current, then you need to look back towards the supply wiring and the DC drive. If wires are OK, then it is the drive.

If you have high armature current and very low voltage (less than 5% rated terminal volts) and greater than 100% current, then you have a shorted motor and the drive should be blowing fuses and setting alarms.

If it appears to be drive side - check all the fuses - there should be AC present at the DC bridge terminals down stream of the line fuses, and your control power should be on.

Just keep following the clues, Watson!
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dks
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Join Date: Jul 2013
Posts: 15
#11
In reply to #7

Re: AC SCR Drilling Rig

03/27/2015 1:58 AM

hello sir!

Thanks for the response. This is a great forum. While I was trying to solve the problem of starting the Mud pump, problem rectified by a domain expert. Tried to get an explanation of the solution it was told that the problem was in the " speed control circuit of the DC module and partly in the in the Driller's console. But myself find it difficult how to check

(1) speed control circuit of the DC module i.e. how to check, what is the input and what is the output in the speed control circuit of the DC module ( my self from electrical background)

(2) what is there in the Driller's console which I can check which is connected to the pump

The rig is E-1400-XI, BHEL make

regards

dks
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dks
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Join Date: Jul 2013
Posts: 15
#10

Re: AC SCR Drilling Rig

03/27/2015 1:55 AM

hello everyone !

Thanks for the response. This is a great forum. While I was trying to solve the problem of starting the Mud pump, problem rectified by a domain expert. Tried to get an explanation of the solution it was told that the problem was in the " speed control circuit of the DC module and partly in the in the Driller's console. But myself find it difficult how to check

(1) speed control circuit of the DC module i.e. how to check, what is the input and what is the output in the speed control circuit of the DC module ( my self from electrical background)

(2) what is there in the Driller's console which I can check which is connected to the pump

The rig is E-1400-XI, BHEL make

regards

dks
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bigg (1); Crabtree (1); dks (3); GW (1); IdeaSmith (2); JRaef (1); Just an Engineer (1); Phys (1)

Previous in Forum: Isolation Transformer on Fuel Supply Pump Circuits   Next in Forum: Fuse Rating

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