Field measurement of harmonic distortion- how?...

[Wond]

My son has a new welder, spec\'d 5% max THD input AC power. I see
Keysight has a DMM with a \"relative distortion\" position. Anyone used one
of these? Useful? Anyone have a favorite, or a simple method? Cheers

 

[Phil Allison]

Wond wrote:
=============

My son has a new welder, spec\'d 5% max THD input AC power.

** The welder is clearly not happy with power from a \"modified square wave\" DC inverter.
So don\'t use one.

Regular mains power is gonna be fine.

...... Phil

 

[Phil Allison]

Wond wrote:
=============

My son has a new welder, spec\'d 5% max THD input AC power.

** The welder is clearly not happy with power from a \"modified square wave\" DC inverter.
So don\'t use one.

Regular mains power is gonna be fine.

...... Phil

 

[Wond]

On Mon, 28 Jun 2021 22:28:19 -0700, Phil Allison wrote:

Wond wrote:
=============

My son has a new welder, spec\'d 5% max THD input AC power.


** The welder is clearly not happy with power from a \"modified square
wave\" DC inverter.
So don\'t use one.

Regular mains power is gonna be fine.

..... Phil

My thinking too, but it appears from available bumf that inverter
types claim less THD than cheap conventional gens.
It would be interesting to see how Agilent/Keysight measure it in
their DMM. Thanks for reply.

 

[Wond]

On Mon, 28 Jun 2021 22:28:19 -0700, Phil Allison wrote:

Wond wrote:
=============

My son has a new welder, spec\'d 5% max THD input AC power.


** The welder is clearly not happy with power from a \"modified square
wave\" DC inverter.
So don\'t use one.

Regular mains power is gonna be fine.

..... Phil

My thinking too, but it appears from available bumf that inverter
types claim less THD than cheap conventional gens.
It would be interesting to see how Agilent/Keysight measure it in
their DMM. Thanks for reply.

 

[Wond]

On Mon, 28 Jun 2021 22:28:19 -0700, Phil Allison wrote:

Wond wrote:
=============

My son has a new welder, spec\'d 5% max THD input AC power.


** The welder is clearly not happy with power from a \"modified square
wave\" DC inverter.
So don\'t use one.

Regular mains power is gonna be fine.

..... Phil

My thinking too, but it appears from available bumf that inverter
types claim less THD than cheap conventional gens.
It would be interesting to see how Agilent/Keysight measure it in
their DMM. Thanks for reply.

 

[Phil Allison]

Wond wrote:
==============

My son has a new welder, spec\'d 5% max THD input AC power.


** The welder is clearly not happy with power from a \"modified square
wave\" DC inverter.

--------------------

My thinking too, but it appears from available bumf that inverter
types claim less THD than cheap conventional gens.

** Oh dear - FYI a \"DC inverter \" runs off a 12 or 24V battery.

\" Inverter generators \" are pure sine wave.
The AC supply has a few percent of 3rd and 5th harmonics.

It would be interesting to see how Agilent/Keysight measure it in
their DMM.

** For sure.
I saw nothing on the Agilent site about it.

Can you borrow a scope to take a peek at the wave?

..... Phil

 

[Phil Allison]

Wond wrote:
==============

My son has a new welder, spec\'d 5% max THD input AC power.


** The welder is clearly not happy with power from a \"modified square
wave\" DC inverter.

--------------------

My thinking too, but it appears from available bumf that inverter
types claim less THD than cheap conventional gens.

** Oh dear - FYI a \"DC inverter \" runs off a 12 or 24V battery.

\" Inverter generators \" are pure sine wave.
The AC supply has a few percent of 3rd and 5th harmonics.

It would be interesting to see how Agilent/Keysight measure it in
their DMM.

** For sure.
I saw nothing on the Agilent site about it.

Can you borrow a scope to take a peek at the wave?

..... Phil