Search results for query: *

Hi I am looking for suggestions. I frequently get asked for a recommendation of plugs 35A plus, that can be used on the output of a VFD using EMC screened cable. Plenty of plugs, but not with suitable screening that transfers through the plug. Best regards, Mark Mark Empson Advanced Motor...

I am working with a customer who has experienced premature PFC capacitor failure in a pumping installation. My customer has a number of large pumps operating off dedicated transformers and an 11KV feeder. The supply authority are insisting on power factor correction, and the motors are...

Anyone got any information on the Matrix Drive efficiency? I am told it is very good, but have not found any figures. Best regards, Mark Mark Empson Advanced Motor Control Ltd

I have recently looked at a number of installations involving VFDs on a stand alone transformer where I believe that there may be a resonance issue. The transformers are rural, commonly fed by 10 + KW of overhead 11KV or 22KV lines and are feeding a VFD. Usually, there is no other load. The...

I am having issues mitigating the harmonics with two Altivar 61 installations. Both installations have variable amounts of even harmonics (2nd 4th etc) as well as triplens in addition to the normal harmonics that I expect. These are the first two Altivar 61s that I have been asked to look at and...

Adding capacitance to a transmission line will cause the line voltage to rise. For a given capacitance and a given transmission line, will adding significant inductance in series with the capacitor reduce the voltage rise? i.e. series resonant between 3rd and fourth harmonics. Best regards...

Hi What would be the typical range of magnetizing current for power transformers in the 50KVA - 500KVA 11KV/400V be? percent of rated current. Best regards, Mark Mark Empson Advanced Motor Control Ltd

Is there a way to disable the DC Bus compensation on the PDL Elite VFDs and the ATV 61 VFDs? We have found this can be necessary to prevent oscillation with drives used with harmonic filters on weak supplies. Mark Empson Advanced Motor Control Ltd

I was recently in a discussion with a group of younger engineers who have a problem with code space in a micro. The code including I2C and serial communications is all written in C and the code space limitation is a major problem for upgrading the product. I suggested that I would rewrite the...

Hi We are currently hearing stories of a number of first turn failure on submersible pump motors. I know that some of these stories are totally incorrect and the first turn failure is a description given by the pump suppliers for other modes of failure, with no evidence of such, it seems to be...

Hi In a situation of severe abnormal bearing loading due to mechanical misalignment and vibration, is the potential breakdown voltage of a bearing reduced? Logic would suggest that as the thickness of the insulating lubrication layer would be affected, the breakdown voltage would also be...

I am looking for a simple means of measuring shaft voltages for EDM investigation. Any recommendations? Best regards, Mark. Mark Empson Advanced Motor Control Ltd

I have a requirement to connect to a Horner PLC via GSM modem at the PLC end, and preferably an analog modem at the computer end. This is for remote programming. First attmepts have not been succesful. Anyone done this?? Best regards, Mark. Mark Empson Advanced Motor Control Ltd

I have very recently come across an organisation trying to sell a mmagic energy saving device in New Zealand. This is a Keseco Ultra Energy device out of Korea. The description claims that they are introducing super conductivity performance into the cables downstream of the device and...

In a recent enquiry into a fatal coal mine explosion, it was suggested that one possible source of ignition of the methane gas, was an electrical arc from the stray voltages cuased by the common mode voltages from VFDs and motors installed underground. Has anyone experienced electrical...

I have been looking at information on the effects of harmonics on the losses in an induction motor. It is commonly accepted that negative sequence currents due to phase voltage imbalance creates a very high slip loss in the rotor of the induction motor. This leads to a derating curve that...

Hi I have a bit of a problem that I can not explain. We are test pumping a new well. The well depth is 230M and the static water level is 113M below the surface. We have an 8 stage submersible pump at 150M below the surface and are trying to run at different levels of constant flow for well...

A recent onsite test carried out to establish the THDi drawn by 6 pumps controlled by VFDs and soft starters yielded unexpected results. We have a requirement that the THDi at the point of supply with all pumps running is less than 8%. There are four pumps controlled by soft starters and two...

I have recently been involved in a number of issues where stray voltages and currents from VFDs have been causing major issues on site. The issues have been shocks to cows in a dairy shed resulting in severely reduced production, elevated cell count and major mastitis in the herd, major...

Double fed induction generators can be used to generate a fixed frequency with a variable shaft speed by driving the rotor with a variable frequency. What are the limits for the mechanical speed range over which this type of generator can be used? most wind powered units that I have sen still...