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Post by racket on Apr 19, 2021 16:55:01 GMT -5
Hi
Having your ignition on the upper side of the combustor can cause problems because propane being heavier than air tends to "sink" to the lower side .
But try this method .............oil on , ignition on , apply blower and get the rotor spinning , remove blower and at the same time feed in the propane , as the RPM decay a point will be reached where a combustable mix is in the spark gap and you should hear the propane ignite , reapply blower and increase fuel delivery as the RPM rise
Can you hear/see the spark in the combustor ??
Cheers John
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Post by rubenpeeters on Apr 20, 2021 3:17:22 GMT -5
Thank you for your reply!
Yes the spark works just fine, we might be adding a sparkplug on the bottom if necessary. We will try to get it to run soon with the method you just mentioned!
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Post by rubenpeeters on Apr 23, 2021 13:45:11 GMT -5
So we just tried to start the turbine. It started running but the turbine wheel started to rub against the heatshield and stopped turning. After it cooled down it was free and turning again. What could cause this?
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Post by racket on Apr 23, 2021 16:48:39 GMT -5
Your thrust bearing might be worn .............how much axial movement in the shaft is there ?
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Post by finiteparts on Apr 24, 2021 17:56:38 GMT -5
Sorry to hear about your bad luck. I agree with John that you could have potentially had an issue with the thrust bearing. A few more comments.
First: if you look at the service manual for the HX80/82/etc....it states that at idle it should be having 3.5 l/min flow at a minimum pressure of 20 psig at startup and 10 psig once it reaches steady state temperature/operation . At full speed it should be flowing 6 l/min at a minimum pressure of 44 psig. If you were not meeting the minimum flow requirements, you could have experienced a rotordynamic instability or had the shaft move forward due to lack of thrust bearing capability. Since it appears that the turbo was used, it could also have had a worn thrust bearing.
It is not clear, but from the images, it appears that the rubs may be only on one side. If this is the case, there might be a possibility that the heat shield distorted locally due to a hot streak. If there is a local hot region of gas coming out of the combustor, it could impinge on the same region of the turbine inlet and thus the local region would be scrubbed with the hotter gas. Since the heat shield is hard clamped between the turbine and the bearing housings, the heat shield would likely buckle outward towards the rotor.
Finally, it should probably be stated, that the rub could be a cause or it could be an effect of whatever the underlying cause may be.
My suggestion would be to disassemble and check all your bearings, check your oil flow rate/pressure and/or buy a repair kit if needed. This is assuming that the rub didn't mess up the rotor balance.
Good luck!
Chris
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