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  1. E

    Monitoring UV output

    "The current sensing is done on the phases at the supply side of the contactor. The physical separation between the current monitors and the ballasts is over a meter away, the ballasts are in a separate ventilated 316 stainless enclosure. The ballasts are very low THD and almost linear load with...
  2. E

    Monitoring UV output

    I think part of the problem might come from the electronic ballasts. They might be causing noise that's affecting the current sensors. A well designed microcontroller based controller/alarm should solve the problem.With 55W lamps you will most likely be able to sense a single lamp failure. I am...
  3. E

    Monitoring UV output

    Hi Marvo, Your approach is a good idea. Maybe you should just look at a custom designed unit, back in South Africa, i made borehole pump control/protection units. Part of the system was current monitoring, the advantage was that i could "fine tune" everything in software... * just to ad, such...
  4. E

    Schneider Zelio Programmable Relay's

    I recently got one from an old control panel, opened it up to sort a diy programming "cable". Although i like Schneider/Tele products, this is not something i would use in an industrial environment. I repaired a micrologix a while back, they are designed/manufactured for more industrial use for...
  5. E

    Dc rectifier

    You were correct, they are thyristors, they just don't want to show you the rest of the gate control circuit! (in case you want to copy their design). Zener diode symbols don't look like that... *they might even actually use the thyristors as in the drawing with the gates left unconnected...
  6. E

    3 Phase Dol starter [help needed on wireing diagram]

    ...
  7. E

    Is this an MCB?

    No!, if you look carefully it's a "x" which indicates a circuit breaker, the "-" indicates a switch disconnector-European std - DIN EN... clearly not similar else what's the use!!! :)
  8. E

    Is this an MCB?

    Hi there, did you guys see the symbol on the front! According to the symbol it's a circuit breaker...:)
  9. E

    How to 'size' contactors for star delta circuit ?

    Hi there, Main = IFL x 0.58 - if your main contactor is in phase, else IFL. Delta = IFL x 0.58 Star = IFL x 0.33 Note your overload size/setting: If your overload in in line the = IFL If your overload is in phase then = IFL x 0.58 Just remember you are starting a motor so choose contactors at...
  10. E

    maths question

    Hi there, I hope this helps...
  11. impe.jpg

    impe.jpg

    • ericks
    • Media item
    • Comments: 0
    • Category: Professional Electrician
  12. E

    Multiple inverter failures

    Hi Jonny, I have quite a bit of exp. on WEG inverters. Need some more info though: 1) What supply to the weg, single or three phase? 2) What is the application? 3) You say they trip often, what is the error code/codes? 4) Do the same one fail or is it random one's? 5) Why do you have a manual...
  13. E

    Shock off shower

    Hi there Justinsane, You most likely have a potential difference between ground and the tap. This means you have a bad earth to your installation. Knock in an earth spike close to your db or shower window. Test ac volts between the spike and the shower tap, or between the spike and the earth bar...
  14. E

    3 Phase Motor Overload Problem?

    Hi Darkwood, You might have misunderstood me. We use MCB's and motor overload / protection devices. Not just a MCB to protect the motor. The whole design is carefully done to match the motor to the mech. drive unit. We always!!! use motor overload devices whether it be thermal / electronic...
  15. E

    3 Phase Motor Overload Problem?

    Hi there, a bit late but if you fit the correct MCB then it should trip as soon as the motor "jams". This is actually a standard by us (in the industry in South Africa). Yous MCB should protect your cable but also the motor against sudden and extreme overcurrents. Thanks :)
  16. E

    E stopping invertor driven motors

    As you have indicated, it is an emergency stop. It should only be used in emergency situations. It is fine to use the e/stop circuit to drop out the supply to the Inverter Drive. But it would not be suitable for regular starting and stopping. Most Drives will auto reset at a loss of supply if...

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