Why MCB trip when turn on Kenwood PSU PD18-30AD

Thread Starter

PUYUP

Joined May 30, 2021
8
Recently I bought second hand power supply Kenwood PD18-30AD. But when turn on MCB trip.
FYI: my home electrical power listen at 900 Watt and 1300 Watt.

In operation docs Kenwood PD18-30AD only use 0 to 1 kW.

Any opinion?
 

MisterBill2

Joined Jan 23, 2018
8,736
First, you will need to read the information tag on the power supply. Then, if my interpretation of the pat number is correct, the output capability is 18 volts at 30 amp. 18x 30= 540 watts output.Butthe input will be more than that. The specifications claim an input draw of 930 watts.
Next, the supply can probably be set up for different mains voltages and it might not be set up for your mains voltage.
And finally, the supply might be defective.
 
Last edited:

Thread Starter

PUYUP

Joined May 30, 2021
8
First, you will need to read the information tag on the power supply. Then, if my interpretation of the pat number is correct, the output capability is 18 volts at 30 amp. 18x 30= 540 watts output.Butthe input will be more than that.
Next, the supply can probably be set up for different mains voltages and it might not be set up for your mains voltage.
And finally, the supply might be defective.
Butthe input will be more than that.

So power supply use 700 watt for standby only?
 

Delta Prime

Joined Nov 15, 2019
994
Welcome to AAC! :)
1,300W-930W=370Watts, remaining
A combination of appliances probably TV ,light bulbs ,fan , everything on simultaneously would trip the breaker.
 

dendad

Joined Feb 20, 2016
3,835
Is it tripping on over current or Earth leakage?
Try wiring an incandescent mains lamp, like 100Watt, in series with the mains Active input and then see if the power supply starts up, with NO load hooked on.
The lamp will limit the input current but allow you to test the supply.
If it still trips, I would suspect earth leakage and it may by mains input filter problems or some other part failure.
 

Thread Starter

PUYUP

Joined May 30, 2021
8
Welcome to AAC! :)
1,300W-930W=370Watts, remaining
A combination of appliances probably TV ,light bulbs ,fan , everything on simultaneously would trip the breaker.
No other electronic turn on.
FYI: I use direct from main cable from MCB. So, no other electronic attached.

Main Installation (electrical service) -> my home -> mcb -> Kenwood
 

Thread Starter

PUYUP

Joined May 30, 2021
8
Is it tripping on over current or Earth leakage?
Try wiring an incandescent mains lamp, like 100Watt, in series with the mains Active input and then see if the power supply starts up, with NO load hooked on.
The lamp will limit the input current but allow you to test the supply.
If it still trips, I would suspect earth leakage and it may by mains input filter problems or some other part failure.
please give a schema
 

MisterBill2

Joined Jan 23, 2018
8,736
Once again my concern is that as a used item that supply may be defective. I have purchased defective equipment several times, but mostly the sellers were honest and told me that it did not work before I bought it. And it was priced as "not working", but I have been able to repair many of those items quite easily. Some repairs are simple and easy and cheap. Some are not.
 

Thread Starter

PUYUP

Joined May 30, 2021
8
Fix. Tested on larger VA working fine. The issue is Inrush Current.
Any here has best tools/circuit to reduce Inrush Current for 1.5kV?
 
Modifying a power supply to soft start may be a fairly big effort, depending on the power supply design,. Changing to a delayed action circuit breaker should be a very straight-forward process that any competent electrician can do in a short time. Of course in some localities that might not be allowed. Or if the system is in a rental property there may be restrictions.

One other possibility would be to try setting the supply output to zero before switching it on. With some power supply designs that would reduce the initial surge quite a bit.
 
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