Variable 60A load

A 20A breaker will trip VERY slowly at 20A. Go read the specifications.

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

heads.

REAL shock and awe.

arabia which are breeding grounds for diaffection

Richard, You are dead-on correct :-(

...Jim Thompson

Strictly speaking the 'B' in DB9 should be the body size of the connector (A - E) the small body used for a 'DB9' is an 'E' size. But for some reason everybody has been using DB9 incorrectly for so long that the 'DB9' term came to be commonly used term.

kevin

Yes, good thinking, a transformer.

If you have a soldering GUN then you have the kind of transformer that you want. Many turns on primary with one or two turns on the secondary. You can probably go to radio shack and grab the biggest transformer that you can find. Unwind the secondary and throw it away. Wind a new secondary with some pretty big wire - depends on how much current and for how long. One or two turns should do maybe. Stick that on a variac and there ya go.

After they have been blown a few times sometimes they seem to trip more easily than when new. Maybe he wants to test it. It's probably cheaper and easier to just replace the breaker, assuming it's a standard household type and not one of the oddball obsolete ones that they charge a fortune for (in which case, it might be better to just move the weak breaker to a circuit that has less load).

Best regards, Spehro Pefhany

The household breakers use thermal trip for overload and magnetic trip for short circuits. The rating specifies the current that is *passed* and not the trip level. It may take several minutes to trip on 25A for example. And it is not enough to test for trip point, the response time also must be measured. The most commonly employed technique is "primary current injection," and the most commonly used, if not only, method is with a high current step-down transformer. This spells weight and cost. You can see an example of a modestly sized one and how it used here:

friendly overtures rather than making empty threats.

Yes, what you are saying is that we need to give Wolfowitz, Rumsfeldt etc their heads. No need for them to argue for a short clinical (but unsuccessful) war - rather REAL shock and awe.

Not just Falluja - but all the Sunni areas and all the poor areas in Saudi arabia which are breeding grounds for diaffection need to be razed - but as you know, this won't happen.

I don't have a solution either :-)

You want happy or you want right?

Best regards, Spehro Pefhany

On Sun, 20 Nov 2005 11:44:21 -0500, Boris Mohar wroth:

higher

Oh OK, it would take 120 200 Watt bulbs. Happy now?

Jim

............ Phil

.......... Phil

"Ira Rubinson"

Current into a load, ie circuit breaker or fuse, is controlled by means of a variac and monitored on a rms amp meter in the primary circuit. The primary to secondary current ratio is the exact inverse of the off load voltage ratio.

OTOH - for the ultimate in portability, try using a C size Ni-Cd cell as a source of high current - 60 amps is well possible.

.......... Phil

"Phil Allison"

Typo alert:

......... Phil

The portable load used to test for high resistance joints in tram rails was a few wooden barrels and some sheets of metal.

The barrels were filled on-site with water and two sheets of metal were arranged in each barrel, parallel but some distance apart. One was connected to the supply (the overhead 550v wire) and the other to the tram rails. Sometimes a tiny amount of salt had to be added to the water to give the required conductivity.

Lifting and lowering the plates would vary the load current. As the water boiled away, more was added to keep the level up. Cooling by evaporation was more effective then by just air conduction.

I do not recommend that you to try this, but just mention it as a matter of historical interest and to show that elaborate equipment is not always necessary.

should be not hard for a go/no go fault tester, but wouldnt test all the waveform recognitions or control magnitude with precision. Much better than nothing though, as it would test a lot of the AFCI functionality.

Motorised contacts with rough surface in series with a load eg a lamp.

NT

like

For

That should be 2400/240 =10 amps only - you need more bulbs. No civilised country would use 120V surely?

McC