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  1. Replies
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    2,140

    Paragraphs and sentences go a long way to making...

    Paragraphs and sentences go a long way to making people willing to help.
  2. 3-phase power is readily available here in NZ but...

    3-phase power is readily available here in NZ but it's certainly not free. Even in a new build situation, you're going to pay a connection fee to the lines company that's about $500 more, plus you...
  3. Three phase doesn't significantly increase...

    Three phase doesn't significantly increase efficiency - higher voltage does that. It does make the utility happy because of balanced power, but that only matters for large users.

    All three phase...
  4. Replies
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    Probably 12-24V AC/DC. Do they have a rated...

    Probably 12-24V AC/DC. Do they have a rated current/voltage?

    You'd be looking for a small socketed DIN-rail mount relay.
  5. Need a bigger cap bank too, though.

    Need a bigger cap bank too, though.
  6. Last photo appears to have been taken with a...

    Last photo appears to have been taken with a potato. Confirm you have three phases plus earth from the drive output to the motor? Do you get equal resistances between phases?
  7. Replies
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    1,689

    They're the same way, just drawn differently. ...

    They're the same way, just drawn differently.

    You can also get a submersible float switch like this and have a foot or so of cable between where it is secured and the actual switch. When it floats...
  8. Most of that stuff is unnecessary, and is the...

    Most of that stuff is unnecessary, and is the manufacturer covering their ass. It's likely that if you read the full manual, most of them have exceptions stating when they are not required.

    The...
  9. Replies
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    515

    Usually you'd use a beam sensor, but the problem...

    Usually you'd use a beam sensor, but the problem is making sure it's blocked when you put something on the conveyor. You may need multiple or a curtain-style sensor. Easier to pick up off the bin...
  10. Motors up to 4kW are typically 230/400. Motors...

    Motors up to 4kW are typically 230/400. Motors 5.5kW are typically 400/690. Using a 400/690 motor allows it to be started star/delta on 400V.
  11. Replies
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    921

    It might also be better to use an SSR per...

    It might also be better to use an SSR per element, instead of one big one for all elements. This potentially allows for control of separate areas, and multiple smaller SSRs are potentially cheaper...
  12. Replies
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    1,058

    Have you measured what the voltage is while it...

    Have you measured what the voltage is while it starts, and what the locked-rotor current is?

    I'm worried that your upstream supply is simply too long and too thin, so you're losing a lot of...
  13. Replies
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    1,058

    How large a supply is there to the machine? Is it...

    How large a supply is there to the machine? Is it sized for minimal volt drop during starting?

    Thermal overloads should go before fuses.
  14. Replies
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    921

    Make sure you check the datasheet and size the...

    Make sure you check the datasheet and size the heatsinks appropriately, and determine what the ambient cabinet temp will be. You often cannot use SSRs at their rated current continuously without...
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    Slight misnomer there, as they're brushless DC -...

    Slight misnomer there, as they're brushless DC - AKA electronically commutated, or VFD-driven AC motors, usually permanent magnet synchronous AC.

    You wouldn't use brushed DC motors for 24/7...
  16. Yeah, cranes and most other applications are set...

    Yeah, cranes and most other applications are set up the same. You almost always want the load to be either stopped, or running in the speed and direction of the motor.
  17. I believe it's usually recommended to use ~370VAC...

    I believe it's usually recommended to use ~370VAC capacitors with a 240VAC supply voltage, as the combination of inductance and capacitance can cause each component to see more voltage than the...
  18. Yup, that's the standard way to wire a brake. You...

    Yup, that's the standard way to wire a brake. You can just remove the wires.

    It's probably best to open up the junction box and remove the brake wires from the splices.
  19. Sure, in extra-low voltage it does and the...

    Sure, in extra-low voltage it does and the fallout if something goes wrong isn't too bad. But your 208V supply and your 480V supply generally won't share a neutral - they'll both be bonded to ground,...
  20. Though shalt not share the same current-carrying...

    Though shalt not share the same current-carrying common between different voltages.
  21. I believe it's virtually unheard of in European...

    I believe it's virtually unheard of in European and Euro-derived drawings like I usually deal with. Most ladder logic implementations have a setting to choose between US and IEC symbols, and IEC...
  22. Yup. What muppet keeps using the symbols for a...

    Yup. What muppet keeps using the symbols for a capacitor for NO contacts!?!?!?! /s
  23. If you end up using a VFD, you would want to...

    If you end up using a VFD, you would want to connect such a valve to one of the relay outputs and use a signal such as 'running at set speed' - this means it will be off (open) while accelerating,...
  24. Hmmm... I wonder if you could run it in vector...

    Hmmm... I wonder if you could run it in vector and set a limit on the torque ramp rate or something? Let the speed vary a bit between revolutions and try to just put constant torque into the...
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    Hey, Nylon bolts have their place. Avoiding...

    Hey, Nylon bolts have their place. Avoiding thermal bridging in coolstores is a common example, and they're also used to provide isolation in some cases.
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