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  1. RyanAspire
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    RyanAspire New EF Member

    Location:
    Kent, England
    [tl;dr] If an item of equipment wanted to draw 16A of current, would it be possible for something else to restrict this? i.e. If equipment wanted to draw 16A of current, is it possible it would only draw 10A (hence making it not operate as it should)? Due to something external of the equipment...?

    Hi everyone, I'm pretty new here, although I've looked at may posts and threads, this is my first post, so any replies I'll be grateful for!

    So... I have a (possible) slight issue that I'm looking for some answers too..

    The issue at hand is I have a rig at work, it heats up hydraulic oil and pumps it round a pressurized system. Pretty simple. The issue is, i has been away to be slightly upgraded (from 1.8bar of pressure to 2.5bar of pressure) worled fine for about 4 weeks and now we have a recurring problem, It wont heat up to its desired target (trying for 90degrees, only getting 65 degrees). There are two of these rigs and they are identical, and the issue is with both of them.

    Now, onto part two. Where they are installed, is on a large circuit, the rigs use a 32A commando plug (three phase), although the supply is much much larger than that (to provide for alot of other equipment), and there is quiet a high current draw on the main supply that feeds all the circuits (including these 32A outlets).

    My first and main thought is obviously that the rigs themselves are faulty after their 'upgrade' and maybe the pump inside it isn't man enough to pump 2.5bar possibly and so it is only the oil in the rig itself that is heating and not the rest of the system. But I wanted to clarify, would there be anything with the install that could possibly prevent this rig from drawing the current it wanted too? For example, if it needed/wanted to draw 16A of current to operate, would there be anything that could restrict it to only being able to draw 10A?

    From my experience and knowledge I would have thought not, I would believe the rigs would draw whatever amount of current that they wanted too, if it was too much for the circuit, then the RCCB would trip (FYI, earth leakage isn't an issue here, approx 4mA of earth leakage on this circuit). I don't believe anything would 'throttle' the amount of current available?

    • Earth leakage not an issue (at 4mA approx)
    • volt drop isn't an issue, it is a short circuit no longer than 15M
    • Rig draws approx 10-14A (is on a 32A commando socket/32A 30mA RCCB)
    • This install is earthed, although I couldn't account for anything before this circuit as it is owned by an external company, and I don't currently have access to any test certificates of the supply. We have had no other issues with earthing though so I would presume all is good.

    Thoughts please!

    And thanks in advance to everyone...
     
  2. SparkyChick
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    SparkyChick Making a banana smoothy for my fave gorilla Electrician's Arms

    Location:
    South Wales
    Business Name:
    SparkyChick
    If it stops at 65 deg C every time and they are both doing it, sounds like there might be a thermostat that is switching the heater off.

    It would be unusual for there to be an unrestricted heat source (for safety reasons), so I'd be looking into the control circuit for the heater.

    What kind of heater is it? If it's just a normal immersion heater, I believe many are preset to around 60 deg C to prevent scalding.

    Just a couple of thoughts to chuck in the pot :)

    Welcome to the forums BTW :)
     
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  3. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    I am with @SparkyChick@SparkyChick your thermostat is not working, or is set to wrong temperature. It may just be it was set at that for safety when converting. A fairly standard setting. Have you spoke to the guys who converted it? As to amps if for some reason 10a was drawn instead of 16a the temperature would continue rising until the thermostat said stop. It would just heat up slower at 10a as against 30 amp say. Personally I think the amps draw is a bit of a red herring.
     
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  4. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Hi Ryan and welcome to the Forum !
    Have you measured the current draw - or are you just thinking it could be a limiting cause? Do you have a circuit diag you could post?
     
    • Agree Agree x 1
  5. LankyWill
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    LankyWill Electrician's Arms

    Location:
    Northants
    Im with SC it must be something related to the stat cutting out the heater. Follow the circuit and make sure thats its connected correctly and that the stat or heater is set correctly.
     
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  6. Pete999
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    Pete999 Trusted Advisor

    Top Poster Of Month

    Location:
    Northampton
    Stat is probably set incorrectly
     
    • Agree Agree x 1
  7. Cadgey123
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    Cadgey123 Regular EF Member

    Location:
    London
    I would be guessing :

    Your rig could have one or more heating elements and you may have lost an element/Fuse allowing it to heat up to the correct temp.

    Faulty thermostat, disconnecting the supply to the heaters prematurely. ( Or it could be set up wrongly )

    Has the upgrade to the machine affected the physical side of the hydraulic system? E.g fluid has a longer run to cool down.
     
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  8. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    Two identical units have both had identical upgrade work, and have now developed an identical fault.
    It certainly points towards the upgrade work having been the root cause of this.

    Is it possible that the increase in pressure has affected the thermostat/temperature sensor?
     
    • Agree Agree x 3
  9. RyanAspire
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    RyanAspire New EF Member

    Location:
    Kent, England
    Thanks for all your replies people, it's really appreciated. And thanks for the welcomes too.

    So a little bit more info, I was in a slight rush earlier when posting. I didn't mean for it to seem like I was expecting 16A current draw (although looking now I can appreciate it does seem like that), I wouldn't know what to expect from it as last year we had no issues and therefore I had no reason to test them at all (for current measurements). I was using 16A as an example is all, apologies!

    My thoughts were initially with it possibly being a faulty thermostat or PCB (it is all controlled via a siemens PCB/interface). After speaking to one of the engineers in the past hour, he has now been made aware that there may be a pressure release valve on it that hasn't been changed. This would therefore open at the new higher pressure (2.5bar) and not allow the hydraulic oil to circulate the system but rather stay in the rig itself. We believe this could be the issue but I'll keep you all posted!

    The only other reason I queried this, is that on the same circuit we have 3 banks of 10 LED lights, all with seperate LED drivers, and when there is a heavy load (i.e. alot of rigs operating at the same time etc), the LED's flicker, this is where I wondered also if there was too much draw could it effect voltage that much that the drivers wouldn't receive the 230V constant that they require. That may be a question for a different thread though.

    Thank you all for your input though it is much appreciated and ill keep you all updated!

    Cheers again!
     
    • Like Like x 1
  10. dmxtothemax
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    dmxtothemax Regular EF Member

    Location:
    Australia
    Business Name:
    David Haddock Electronic Repairs
    • Like Like x 1
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