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Thread: MCE product review

  1. #11
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    This weekend I decided to pull all MCE contactors ... the stock I bought to try keep the site going ... I will be returning.

    It is just not worth it ... everytime I loose a contactor ... the ripple effect in the control circuits using control transfomers with low VA ratings is far out weighs the couple of rand saving using MCE ... even if I was the maintenance electrician at the factory ... the machine downtime ... production losses ... all this requires consideration.

    After wasting many hours trying to find a solution to protect the transformers ... I learnt a lot but at the end of the day ... not worth hassle.

    The blue flash as the contactor makes and breaks ... the high inrush current ... the higher running current compared to other contacotors I researched ... may not be an issue if you have a neutral from the DB sealed the decision.

    Maybe the product is good for other applications ... as mentioned by others ... but not in my case.

    You live and learn.
    Comments are based on opinion...not always facts....that's why people use an alias.

  2. #12
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    So we had another 2 contactors fail today ... I have contacted a another supply company company to try a different brand to see if it is the product or the design and installation.

    I spent a few hours going through the thermal scans of the control panel ... and found something rather interesting ... the ambient temperature in the panel ... around 30 degrees C ... above the contactors around 53 degrees ... considering there are coils which generate heat ...would seem a little high but ok ... also considering it is the same above all the contactors and evenly spread... but here is the kicker ... 97 degrees between the contactor and overload ... if I look at the thermal scans facing down towards the overload ... the heat seems to be coming from the overload ... yes I have removed the contactor and overload and checked the connection are correct and that the pins are behind the steel plates ... you would see if there was a loose connection or if the overload pin was in front of the plate ( a common problem I pick up when doing thermal audits for companies) by an uneven thermal profile across the terminals.

    I have checked and rechecked the voltages and load balancing across the motors ... if there was a problem the overload should ave tripped ... the load tests are lower than the rated amps on the motor name plate ... the contactors and overloads are slected correctly for the motor size ... I have checked and double checked.

    Please feel free to comment or offer advice ... I am all ears ... I need to find a solution and soon ... this fiasco is starting to cost me a lot of money.

    I am still waitng for the reports from MCE ... and the next 2 will be sent off tomorrow for investigation.

    Something else I found interesting ... when the motors are started in the morning and switched off in the evening or run for a couple days without stopping ... there are no issues ... however if the motor is stopped during the day and the motors are restarted soon afterwards ... bang that is when the coils in the contactors pop and the circuit breaker trips ... looking at the overload temperature profile ...could that be the problem.
    Comments are based on opinion...not always facts....that's why people use an alias.

  3. #13
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    Just to clear up any confusion ... the contactors and overloads are being used for various applications ... some run heaters ... motors ... pumps ... fans ... of diferent sizes ranging from 0.5 watts to 5.5 kw.

    For example #12 is not the same panel as #8 ... the only thing common is the replaced switched gear.
    Comments are based on opinion...not always facts....that's why people use an alias.

  4. #14
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    Note that motor overloads consist of resistance wire, whose resistance value is proportional to the amount of heat generated in a bi-metal trip switch. In other words, heat must be generated in order that the overload can detect when there is an excess amount of current being drawn by the motor.

    Now this could be a few watts depending on the amount of current flowing through the resistance element wire.
    Add the heat created by the contactor coil, also a few watts, add the heat generated in cabling from the main breaker, add the the heat generated by the wire from the overload to the motor, and there is a fair amount of heat generated by each motor control circuit. Now add a number of these circuits, all inside a closed control panel, and running for hours and hours, and all of a sudden you have a nice heater box, now add one more variable into this mix, ambient temperature which at the coast could be around 40°C, and you have a situation in which there is going to be failures because of the heat buildup.

    Had a situation like this some 40 years back, We had measurements of approximately 90°C when the panels were closed, and doors closed, by the way these were free standing 2 meter high control panels. Our final solution was to split the number of motor circuits across 2 DBs, in other words reduce the amount of switch gear by half, and increased the wire size to reduce the heat generated in the wire, and the problem did go away. Was a huge job to rewire the DBs.

    You could consider using electronic overloads, as the amount of heat generated by these detectors is equivalent to the transformer wattage.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

  5. #15
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    I moved the contactors and overloads in the DB ... but too scared to switch off and restart to test... the plant closes today so I can do the mods over the weekend.

    When the plant closes I will be removing the D curve breakers and overload relays ... replacing them with motor starter breakers mounted in the main DB (reducing the amount of gear in the DB and control panel) ... Replacing the Contractors with a diffrent brand and modifying the wiring to suit ... lets hope this will resolve the issues.

    We live and learn.
    Comments are based on opinion...not always facts....that's why people use an alias.

  6. #16
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    MCE did offer to replace everything ... unfortunatley I cannot afford to take a chance and therfore declined their offer.
    Comments are based on opinion...not always facts....that's why people use an alias.

  7. #17
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    Removed the last of the MCE products today ...tomorrow I collect the new control panel and start building the new panel ... hopefully by monday morning it is ready to install ... by Tuesday we can start commisioning.
    Comments are based on opinion...not always facts....that's why people use an alias.

  8. #18
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    I removed the entire control panel and all the wiring ... got an electrical engineer to assist ... put the panel on the workbench and stripped it wire by wire ... then stripped the components one by one ... checking for loose connections ... heating on terminals ... checking the bootlace terminals for discolouring ... checking the wiring in the slotted trunking ... checked the contacts on the omron relays ...all good.

    Each terminal is tightened and marked with a red marker ...so i didnt expect to see any loose connections.

    looking at the thermal images ... was expecting to see discolouring inside the overload relay ... there wasnt any.

    The only fail parts which indicate there was a problem are the contactor coils ... the plastic in the centre of the coils have melted which restricts the movement of the metal ... and a thin black strip around the outsde of the coil showing signs that it overheated.


    The conclusion : The contactors coils are failing for whatever reason ... none of the other equipment coils have failed (the ormon relays or level control)

    I am going to reassmble the stuff and send it back to MCE ... I have still not had any feedback from MCE with regards to all the other contactors and overloads already sent to them.
    Comments are based on opinion...not always facts....that's why people use an alias.

  9. #19
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    It seems like the issue with this product had something to do with operating temperature ... it seems it was destined to fail ... still waitng for my credits.

    The new equipment operating in the same environment and ambient temperature ... just at a lower operating temperature.

    Which reminds me ... as soon as I get a break I need to go scan the panel.
    Comments are based on opinion...not always facts....that's why people use an alias.

  10. #20
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    Here we sit on the 1 August 2021 and MCE have still not credited the products returned.

    The lesson we learn from this ... not only will the product fail ... the call out fees and time wasted replacing product ... lost time for the staff on site ... but you will not be refunded.
    Comments are based on opinion...not always facts....that's why people use an alias.

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