Power meter GW Instek GPM-8213

[PP7BB]

Anyone use this power meter?

https://www.gwinstek.com/en-GB/products/detail/GPM-8213

I got this and want to use the thing to measure electronic power supplies. Unfortunately those usually have big inrush currents - up to 80A for about 200 microseconds. This device has label 20A rear/10A front panel socket max and cant find any info if it is maximum continous current or maximum peak current allowed. It is my first power meter and I think I misunderstood its description or saw wrongly prepared product card - I remember I saw that meter is able to measure devices up to 6000W of power. Do I destroy meter if inrush current of measured device exceeds 20A over even very short period of time (hundreds of microseconds)?

This power meter can utilise current converter (CT) so its current range can be easily enlarged. I am not sure if measuring harmonics is still possible while using converter. Can anyone explain this? Don't know converters and their frequency characteristics...

[nctnico]

The specification says that the maximum current is in RMS. Not peak.

[electr_peter]

Datasheet says 20A with crest factor of 3 (or 10A with crest factor of 6). So 60A would be no problem. Peak of 80A is slightly higher, but should not do any harm.
Continuous high current is a problem because it can melt internal shunts/fuses if left for prolonged amount of time. Peak current does not cause the same heating issue.

[PP7BB]

I got email from GWInstek, cant tell if he is engieener or sales man. Hes only response is that maximum current allowed is 20A, nothing else. I gues he is from sales...
Thank You guys for advice!
BTW - I am thinking about CT converter to strech current range. Can You recomend some of this devices? I haven't much experiences with such devices to measure current. I would like to get converter wich enables measuring current harmonics. Instgek GPM-8213 works up to 6kHz... Am new to this topic. Do You know any converters wich can work up to this frequency and precise enough to do the job?

[PP7BB]

Quite hard to find current transformer with higher frequency range (not to mention the price ;-) ). Measurement of current with frequency 50/60hz is simple but I want to measure THDI - current harmonics with this meter.
Anyone?
I have never had to choose such device, am afraid I will stuck with this.
I see on internet only some suppliers with devices wich can operate on  few up to tens of kHz, but don't know if their frequency response is flat or will make THDI measurements impossible.
Can You guys advice on such devices? GPM-8213 operates up to 6kHz to sample current waveform, how to choose such transformer?

[RBBVNL9]

Hi PP7BB,

For measuring high currents, you may not want to run them through such a device but use an external current sensor instead (possibly contacless). But AFAIK the GPM-8213 model does support external sensors.

The 'next' model, the GW INSTEK GPM-8310, does have two external inputs for external sensors and quite a high degree of adaptability to the characteristics of these sensors.

If measuring high currents is important to you, and doing so contactless is appealing to you, you may want to see whether you can still swap the device you purchased.

See also the below video for a detailled review of the GPM-8310:

[French_Nikolas]

The GW-Instek documentation of the GPM-8213 states :

« Peak Current           P.I            The current exceeds the measurement range » (p. 22)

« The maximum input current is 20Arms. The device will issue a warning sound when the input voltage and current exceed 700 Vrms or 25Arms. » (p. 50)

« Maximum display voltage                                700 Vrms*
  Maximum display current                                 25 Arms*
  Maximum allowable isolation voltage                 300 V
  Low frequency filter         Cut-off frequency       500 Hz

  * When measured voltage/current reaches the maximum scale (700 Vrms/25 Arms), the buzzer sounds loud for alert. In addition, It is suggested to have measurement within the safety scale (600 Vrms/20 Arms) in case of irreversible damage to the unit. » (p. 107)

I think that the main risk is the power dissipation of the shunt (5 mΩ).
Between 20A and 25A, the dissipation increases by 50%, so for a very short period, this should be fine. It should also depend on the ratio between the rated current and the peak current.