Star Delta Panel (A Practical Experience)
This may be not new to everyone, but is just another work experience and is posted by a request from the admin.
This was a work done in a fuel barge here. It consists of diagnostic and assembling a Star delta Starter for 440V/660V AC 10KW induction motor that is used to drive the diesel pump in a fuel barge.
As I have stated this is just for the general info and the names, may that be of a person or a vehicle, are only on need to know basis.
The Initial panel was burnt to a crisp as I would define as one phase was completely over loaded, may be due to motor burning out or may be due to one phase cutting off.
The Contactors and overload plus the timer contacts were melted and the wires insulation have literally melted. The whole panel has to be remade with new parts.
But before disconnecting the panel, further examination were carried out to see whether the motor connection were proper and at first glance the motor was wired in Star configuration to the delta contactor.
Investigation revealed that another tech had repaired after a repair trip to the yard and the panel shorted outed after a while when they powered up the pump.
So what is done is done and My job was to get it up and running.
The panel was redesigned with proper wire gauge and as per regulation. The Motor is started in star configuration and switched to Delta after a predetermined time.
This is done to minimise surge current over load to the generator as the motor would overload if started at it's full capacity.
The star config alows the motor to run at 50% RPM and loads much lightly. As the motor rev up to the desired rpm the windings will be switched to Delta where the motor will run at it's rated rpm. (the time period depends on the motor rpm and the load and differes from app to app).
The swittching of the windings is done by heavy duty contactors ( 3 of them are used. one for strar, one for Delta and one for the main cutoff). A timer is used to swicth the contactors and another 4 pole MCB is used for parmenent power disconnection. The motor current is monitored by a 3 phase overlaod contactor and is wired in to the main contactor switching circuit.
The control has a simple on and an off swtich and the power lamp indicators.
Below you can see the pics
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F100_8887.jpg&hash=0651303ad66a32a7290c609b3ba4d66f)
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F100_8886.jpg&hash=bd2c76015d3457c12d3fd560fc75705f)
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F100_8885.jpg&hash=2c906513bc997e401966c5d881763ad4)
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F100_8892.jpg&hash=f3dab45f264c790d590199a8beb89d8d)
This is a basic panel looks like and is powered by 4 pole 3 phase 440VAC Genset.
The initial testing of the panel went flawlessly.
After fixing it and before the motor wire connection, the resistance winding was checked for shorts and revealed that motor has burned windings, and to prove it to the captain I had to wire up and start. But before that Supply checking showed that One phase is missing and the phase voltage is below 200V 😕.
Further checking was done in the main panel and the genset and it seems that the some one has wired a three phase panel into the boat and the genset was indeed a 4 pole 3 phase geneset but the power cable wiring was done in single phase. Further more to make things a bit odd, it had 2 phase at 200V and two neutrals. Now who with a right mind would do so. 😔.
The connection was changed over to the proper power output terminals and the neccessary changes were made the panel wiring.
After power up the barge light was brighter than before, since now the appliances has 230VAC instead of 200VAC. Major improvement after 4 years. Get that 4 years .
Now for the pump start up, after terminating the wires the motor started perfectly and when it switched to delta the genset died out and the Main plus overload tripped indicating a burned motor.
Nothing else were damaged since the panel can withstand Motor overloads indefinitely. The motor is now sent for repair. till then, signing out.
Rifaa
This was a work done in a fuel barge here. It consists of diagnostic and assembling a Star delta Starter for 440V/660V AC 10KW induction motor that is used to drive the diesel pump in a fuel barge.
As I have stated this is just for the general info and the names, may that be of a person or a vehicle, are only on need to know basis.
The Initial panel was burnt to a crisp as I would define as one phase was completely over loaded, may be due to motor burning out or may be due to one phase cutting off.
The Contactors and overload plus the timer contacts were melted and the wires insulation have literally melted. The whole panel has to be remade with new parts.
But before disconnecting the panel, further examination were carried out to see whether the motor connection were proper and at first glance the motor was wired in Star configuration to the delta contactor.
Investigation revealed that another tech had repaired after a repair trip to the yard and the panel shorted outed after a while when they powered up the pump.
So what is done is done and My job was to get it up and running.
The panel was redesigned with proper wire gauge and as per regulation. The Motor is started in star configuration and switched to Delta after a predetermined time.
This is done to minimise surge current over load to the generator as the motor would overload if started at it's full capacity.
The star config alows the motor to run at 50% RPM and loads much lightly. As the motor rev up to the desired rpm the windings will be switched to Delta where the motor will run at it's rated rpm. (the time period depends on the motor rpm and the load and differes from app to app).
The swittching of the windings is done by heavy duty contactors ( 3 of them are used. one for strar, one for Delta and one for the main cutoff). A timer is used to swicth the contactors and another 4 pole MCB is used for parmenent power disconnection. The motor current is monitored by a 3 phase overlaod contactor and is wired in to the main contactor switching circuit.
The control has a simple on and an off swtich and the power lamp indicators.
Below you can see the pics
This is a basic panel looks like and is powered by 4 pole 3 phase 440VAC Genset.
The initial testing of the panel went flawlessly.
After fixing it and before the motor wire connection, the resistance winding was checked for shorts and revealed that motor has burned windings, and to prove it to the captain I had to wire up and start. But before that Supply checking showed that One phase is missing and the phase voltage is below 200V 😕.
Further checking was done in the main panel and the genset and it seems that the some one has wired a three phase panel into the boat and the genset was indeed a 4 pole 3 phase geneset but the power cable wiring was done in single phase. Further more to make things a bit odd, it had 2 phase at 200V and two neutrals. Now who with a right mind would do so. 😔.
The connection was changed over to the proper power output terminals and the neccessary changes were made the panel wiring.
After power up the barge light was brighter than before, since now the appliances has 230VAC instead of 200VAC. Major improvement after 4 years. Get that 4 years .
Now for the pump start up, after terminating the wires the motor started perfectly and when it switched to delta the genset died out and the Main plus overload tripped indicating a burned motor.
Nothing else were damaged since the panel can withstand Motor overloads indefinitely. The motor is now sent for repair. till then, signing out.
Rifaa
Replies
-
Kaustubh KatdareGreat going, dude! 😀 -
Harshad ItaliyaNice one Rifaa Keep them Coming
-
RifaaI do these kinda things all the time. I use to visit luxury yachts and cruise launches of those kinda guys who likes to travel around the world and stuff. When they break up during their coarse in Maldivian waters, I'll be the one on it. Pretty hectic life I have.
Tourist resorts visits are pretty fun too
Rifaa
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