Search results for query: *

Hi All we had the motors rewound with standard winding wire restored to as new condition. We ran the motors at the same voltage with the same drives under the same environmental conditions. i.e. same, same, same, same... we made a simple low cost modification which my customer is holding close...

Hi mikekilroy its not a overtemp failing of the windings. we have inspected and found areas of where the windings insulation has been failing. there is no discolouration. there is degradation of insulation coatings. but not temp related. insulation coatings also outgas... yes our squirrel...

Hi Chasbean1 notes to your questions below. 1) How are the 30°C temperatures measured while the system is near a perfect vacuum? Measurement methods might be suspect without air. --> the temps were measured with a infrared temp sensor pointing at the hub in various locations when under a...

Hi Mikemay and btrueblood and dread We had looked into the old vsd setup. It is an old pdl xtravert drive with no output filter and 4kHz switching frequency. The new vsd with sinusoidal filter was set to have the same 4kHz switching frequency. The old machine is in a different city and is in a...

FYI an update - we are currently doing a test in the original machine with the new fan. We are half way through a week long test. If the new fans do not survive then it indicates that the fans manufacturer has changed the insulation...if they do survive then the issue is probably a combination...

Thanks BillPall Moving the motor outside of the chamber is difficult due to the chamber being a very tight fit inside a container. so cant put the motor outside. ideally we want to rewind the motor with winding wire with the correct insulation to survive the vacuum. regards ryan Ryanmech...

Thanks wktaylor Yeah - Russians fans could be difficult to procure. They will prob be low voltage dc motors. For our situation, a fan has been running in the same vacuum environment for 10years. The new fan is not surviving. We think that the winding insulation has changed over the past...

Jraef - great suggestion thankyou - we will look today Regards Ryan Ryanmech Scott Technology Ltd NZ Machinery automation

Hi The fans run fine at normal atmos conditions. Its just a squirrel cage motor with the cage embedded in the fan hub. We rewound a motor but it failed in the same manner. Earth fault. It is not a perfect vacuum so there is still air 5%. A fan moves the air to some degree. All theory points...

Hi DB thanks for the link yes understood - we are in contact with these people but are yet to hear back from them. Hi Chicopee we are in contact with a company which may be able to assist us - yes NASA does have a lot of info - what we are after is people with practical experience solving...

Thanks Mike any idea what a suitable voltage would be to avoid partial discharge at 5kPa absolute pressure? thanks and much appreciated regards ryan Ryanmech Scott Technology Ltd NZ Machinery automation

Hi Short question: What type of winding insulation should be used for a fan motor that is within a vacuum? please see details and PLEASE RESPOND in the thread: http://www.eng-tips.com/viewthread.cfm?qid=395029&action=updated all suggestions much appreciated regards ryan Ryanmech Scott...

Hi Scotty thanks for the suggestion to post on the aircraft and aerospace forums - according to compositepro I would be further outside the posting guidelines.... cross posting etc. Hi EdStainless and MikeHalloran I am really looking for a motor manufacturer who is specialised in motors in a...

Thanks Keith Yes we found empiremagnetics people on Thursday... Indicatively they are very expensive....well lab equipment expensive... We will contact them next week. in the mean time we are looking for advice from a engineer with practical experience in insulating motors in a vacuum...

Thanks Keith The application does not lend itself to have the motors outside of the vacuum chamber due to other constraints. The previous machine has worked with the same fan model for ten years with no issues. We think the fan motor insulation has changed in the past ten years. The fan motor...

Thanks Zappedagain Yes agreed that vacuum and raised temp increases the distance that an arc can form. Or in scottys terms partial discharge will occur at a smaller distance between potentials at reduced pressure and increased temp. In our case 400Vac between windings -600 to +600V. 1.2kV...

Thanks compositepro Yes - I can see why you posted the same answer! Just aswell I gave you the same Response! Apologies for your double response. Yes - I agree your opinion of how a vacuum drier works is off topic and unrelated. This question is about motor winding insulation for vacuum...

Thanks Scotty I appreciate your time and expertise. Yes - motor insulation for vacuum seems to be very specialised. Yes I agree that HV PD and PD at reduced pressure are closely related..... Lets wait and see if a member has the practical experience in motor winding insulation for protection...

Hi ScottyUK yes the uni paper directs us to use Teflon for winding insulation on motors subject to vacuum. Teflon/PTFE due to its resilience against outgassing, and subsequent insulation degradation, and corona discharge. we are investigating the use of Teflon sheet for isolating the windings...

thanks Compositepro same response to your condensation suggestion in my HVAC post regards ryan "thanks Compositepro we had inspected the motor and there is no moisture and no condensation on the motor. in any case the dew point of the moisture would not form on the warm windings. we...