Electronics > Beginners

my cook top hates my heatpump?

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ogden:

--- Quote from: Monkeh on October 30, 2019, 03:05:13 pm ---16kW heat pump. That's the heat transfer rating, power consumption should be just over 4kW, maybe edging over 6kW in the worst case. Not particularly scary.

--- End quote ---
Whatever is electrical power of that heat pump - AC voltage droop shall be checked anyway. Could be The Reason.

Berni:
Yep heatpumps are usually rated for the heat output power in kW (Since that's what you care about) so this is actually all the input power plus all the heat it pulls from the environment. For marketing purposes this number is cherry picked from the best case combination of outdoor and water temperature so will rarely even be reached in practice.

To get 16kW of output it probably needs about 4 to 5 kW of electrical input power. The 4kW number is quite common because 20A circuit breakers are common for heavy loads in households. And this is likely where the problem is, this is a lot of power for a usual residential service and so depending on how good the wiring is this could cause a significant drop in voltage for anything on that phase. To make things even worse induction cookers are also very heavy loads that can consume anywhere from 1.5kW to 6kW or even more, combine the two and the voltage could drop even more and it could be that the induction cooker is the first to throw its arms up and give up when it notices its not getting enough voltage to work.

If you have three phase power available (It is common to have 3 phase in residential here) then the fix is easy to move the heavy loads onto different phases by just moving the circuit breaker in the electrical cabinet. If you have single phase power then there is no such easy fix. In that case i would measure the mains voltage on that phase and see if it is within your governments regulations regarding power quality (Here it is i think -15% to +10%). If the voltage at your mains feed falls outside of these limits then the power company is required by law to fix it. I had to do this once and upon complaining to them they brought there own measurement gear and dataloged the voltage of all phases for a week before saying it is indeed out of tolerance and running a new cable.

EDIT: Also make sure you are within your rated power for your mains service. The oldschool main fuses are quite wide in tolerance so it is possible to pull say 30A on a 25A main fuse. In that case the power company may force you to upgrade to the correct service power and pay more on your electricity bill accordingly before they would do anything about your complaint. Here they fixed the tolerant fuse problem by using the new smart meters to monitor current and disconnect in the event of an overload rather than rely on the main fuses to blow if you draw more than what you are paying to get.

inductive:

--- Quote from: Monkeh on October 30, 2019, 03:05:13 pm ---
--- Quote from: ogden on October 30, 2019, 02:51:58 pm ---What is nominal power of your mains feed? 16KW (!) pump is quite a load load for single phase rural power line. First obvious thing to do - measure AC voltage while pump is running.

--- End quote ---

16kW heat pump. That's the heat transfer rating, power consumption should be just over 4kW, maybe edging over 6kW in the worst case. Not particularly scary.

--- End quote ---

right now i measure 228 volts between N and L on the breaker for the compressor


the pump is a beast, but is only delivered in single phase.

it maxes about 7kw.

but, there is also two backup heaters in the indoor unit (combi unit with domestic hot water). they are set at 3kw each for the time being. but can be set to 6kw each, and the indoor unit has provisions for going 3phase

i do have 3 phase cable into the house, but the last phase is not hooked up. (freggin expensive, both to have done, and the extra montly/yearly costs just bare having 3phase 63A). but at some point this will be done, but not now.


i'l have a look into the voltage leveles over some time

inductive:
one qick question, what would a normal voltage balance be?


L to Ground: 116,3
N to Ground: 144,7

L+N:  229,4

there are some variatons in voltage. but only 3-4 volts

noidea:
Just a lowly non Electrial Engineer HVAC tech here but a few comments for the mix.

A 16kW unit is probably on a 30 Amp single phase supply.

I found what I think is the right service manual for your model on the net ERLQ011-016CV3 can you confirm the model number? If it is and the noise is only happening when the compressor in the heatpump is running then it most likely related to the active power factor correction circuit (V2R, V3R, V1T, L1R) section of the A1P board and not the power transistor module thats creating the three phase for the compressor.

I have worked mainly on other brands than Daikin but this style of Inverter power circuit design, with two bridge rectifiers, an IGBT and reactor coil is pretty common if a discrete active filter module is not being used.

If I had to guess I would suspect it is more a conducted than radiated emission issue as you said you can hear some noise on your desktop PC as well. I would guarantee that the AC unit is compliant to the relevant test standards Japanese manufacturers tend to be pretty honest about this, but it will be very tight to the standard.

The IT wiring system is interesting, the A3P board contains the noise filtering circuit and should be bleeding the noise in the unit to ground. In Australia we use TN-C-S and I know from experience faults in the earthing / neutral earth bonding tend to make noise issues worse here.

I'm sorry I can't really offer much in the way of how you actually test this in the field, I would like to know myself  :)

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