Cutler Hammer Soft Starter

[iceman007]

I played around with the soft starter on a Trane CVGF chiller today. It keeps tripping out with the motor running. Initilly it would get to 70% FLA and then trip, so I went to look at it and found it was a overheat fault. Then it would also trip out on zero voltage cross, and bypass failure as well. I went today and with my idea that the settings had been changed. Sure enough the settings were in need of changing, so I programmed the torque, and the ramp up and coast down times etc. Ran the machine and it went to close on 100%. It only failed when we turned on the other chillers and lost the evaporator water flow. Then after that it started tripping again. My thought is that the power supply is the culprit. I am getting 23.8VDC and think (after talking to Cutler Hammer) it should be closer to 25VDC as the current supply is too weak to hold the bypass contacts and it's also why the zero voltage cross fault is there. The thing is I cannot increase the voltage no matter how hard I try, even changing the control transformer connections to clean up the voltage. It's a T801V starter and I am running out of ideas other than the power supply.

?????????????

[simon@parker]

hi iceman volt drop down to cable size on ac stuff any help ? or could be yr bridge rectifier if it separate to transformer they slippery buggers also if all yr contactos are using the trans former you can fit smoothing capacitors to coils haved seen it done on big panels stops contactor chatter an buzzin

[simon@parker]

had brain wave if its fed off a pcb check joints might be a dodgy one dry joint or corroded just a thought

[iceman007]

had brain wave if its fed off a pcb check joints might be a dodgy one dry joint or corroded just a thought

Checked cable size and that's correct. Contactor is internal and auxiliary (three of them to the SCR's). I can't get the voltage up to 25DC

[simon@parker]

hi iceman
check the voltage coming in is correct an not low then check individual phase voltage if that ok check cables themselves to yr transformer and from it for damage and resistance if ya got a volt drop ya either have low volt comin in to unit or somat dragging it down sorry if i teaching u to suck eggs hope it helps let me no have a good one

[iceman007]

hi iceman
check the voltage coming in is correct an not low then check individual phase voltage if that ok check cables themselves to yr transformer and from it for damage and resistance if ya got a volt drop ya either have low volt comin in to unit or somat dragging it down sorry if i teaching u to suck eggs hope it helps let me no have a good one

It was low. 112v and supposed to be 115v so I made a few adjustments to the tranny, and got tht to 115.7VAC. So I thought to myself it would be Ok now, but still 23.8VDC output.....

[simon@parker]

pain in the arse this one lol could be your neutral line not connected very well only other thing if ya checked everything else your transformer could be iffy ? if ya have a similar unit try trany in that an vice versa let me no these things give ya sleepless nights lol

[goshen]

I played around with the soft starter on a Trane CVGF chiller today. It keeps tripping out with the motor running. Initilly it would get to 70% FLA and then trip, so I went to look at it and found it was a overheat fault. Then it would also trip out on zero voltage cross, and bypass failure as well. I went today and with my idea that the settings had been changed. Sure enough the settings were in need of changing, so I programmed the torque, and the ramp up and coast down times etc. Ran the machine and it went to close on 100%. It only failed when we turned on the other chillers and lost the evaporator water flow. Then after that it started tripping again. My thought is that the power supply is the culprit. I am getting 23.8VDC and think (after talking to Cutler Hammer) it should be closer to 25VDC as the current supply is too weak to hold the bypass contacts and it's also why the zero voltage cross fault is there. The thing is I cannot increase the voltage no matter how hard I try, even changing the control transformer connections to clean up the voltage. It's a T801V starter and I am running out of ideas other than the power supply.

?????????????

Hi:
had plenty of problems with these ss .
if u want to increase the voltage on the power supply ,u should have small potentiometers on the supply itself ,that u turn while messuring the voltage, and set it to the correct voltage .u cannot change the voltage output of a regulated power supply by increasing the primary voltage or changing the wires!!
only by setting .
u are defenatly in the right direction these soft starters are very sensitive to power fluctuations.
i would also suggest u check and make sure all relayes that should be 24vdc are indeed 24vdc and not 24vac !!trane had a whole batch of wrong voltage relayes put in on some units.
u might also consider a new and stronger power supply 115vac to 24vdc 10amp
good luck.

[fusbblood]

if the power supply is of a "switched" type then adding load to the power supply beyond the power supplies capabilities will result in a voltage drop. This is a design feature to protect the power supply and circuits. (limits current design to max)
measure and set the output to 24vdc with no power being drawn from the power supply. Any drop in voltage then means you need a meatier power supply. A 24vac relay coil will draw a lot more current than a 24vdc coil in a dc system.

[goshen]

hi well said .!

[allpro]

we never stop learning

[goshen]

we never stop learning

Hi life indeed is one big lesson !!