Help: Connecting two Fluke meters in series

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Well - it should work, but Fluke makes high voltage probes and that is a better way to go. Or-- one could make a voltage divider with resistors of known value. Like a 100K in series with a 10K for a 10 to one ratio, then measure accross the 10K and multiply by 10.
 
Of course,

in principle it should work. But the division ratio of the voltages then depends solely on the internal resistances of the two meters. If they are not equal, one will see a higher voltage, possibly higher than its specifications. If it reacts by arcing or failing s/c, the second meter will be shot, too.

A high voltage probe is the best way to go, certainly cheaper than replacing two Flukes. If not available, an appropriate voltage divider as described by you would be best.

Greetings,
Andreas
 
However, I have two Fluke 87V. Each one is only 1000V max. So even if I have the high voltage probe, the meter would not read that high.

Sorry but I think you misunderstand the way a high voltage probe works. Usually they divide the voltage down by a convenient ratio, or they contain active electronics which convert the high voltage range into a convenient DMM range, such as 1000V -> 1000mV.

With the probe you mentioned, any standard DMM can measure voltages in the kV range.

Regards,
Andreas

PS. Of course your meter can not read more than 1000V, it will show a value that has to be converted then!
 
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I found the connector that I mentioned.
It is Fluke TL222.
 

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I'm sorry if this is being perceived as rude. That isn't my intention. But I'm a bit concerned by the perceived mismatch between the technical level of your questions and the technical level of what you are trying to do...

High voltage probes are essentially voltage divider. They divide the measured voltage by typically 10 or 100. So if you have a Div-by-100 probe, the meter will read 100x less than the measured voltage. I.e. if measuring 100 kV, the meter will read 1 kV. I sincerely hope you aren't measuring those kinds of voltages, though...

Even a few hundred volts can kill you without thinking twice about it.

~Tom
 
The 'connector' is nothing special, just a simple test lead. You will find lots of them in any electrical lab/workshop, as its 4mm pin size is a standard which allows to connect most electronic test equipment as DMMs, signal generators, component testers, power supplies and so on.

Greetings,
Andreas

Edit: I have to agree with Tom concerning your level of knowledge and the risk that is connected with high voltage circuits. I would strongly recommend some basic reading and the high-voltage safety thread at the top of the tube subforum. It is no offence, just don't want to lose DIY audio colleagues to some bunch of electrons.
 
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I found the connector that I mentioned.
It is Fluke TL222.

This lead is not in any way meant to be used to connect two meters in series to measure >1000V.

Some people have made rather oblique references but here's the straight deal:

The very idea of connecting two meters in series to increase the voltage capability is extremely dangerous and misinformed at best. No one should get the idea that it's in any way acceptable to do this. The voltage rating of the meter is based on it's insulation system including leads and case. No component is rated for >1000V, including to ground.

It's very difficult for me to believe that anyone who has to even ask this question should be involved with a 1500V system. Period.

It seems like you have identified the correct solution that a qualified technician would use, which is a high voltage probe or high impedance voltage divider.

I'm more than a little concerned as one who has published schematics on this board with 700V-1500V B+
 
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Well - it should work, but Fluke makes high voltage probes and that is a better way to go. Or-- one could make a voltage divider with resistors of known value. Like a 100K in series with a 10K for a 10 to one ratio, then measure accross the 10K and multiply by 10.

If you're going to build (or suggest to build) a divider for this please work out the power dissipation (110K ohms at 1KV is 9 watts!), also common resistors are only rated for about 250 volts.

The high voltage stuff is no place for guessing games and half thought out ideas. Please
 
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Two things to consider.
1. What's the insulation resistance of your probes at 1500v.
2. What's the load (meter & probe impedance) going to do to the voltage you are trying to measure.

Your probes should be rated at 3000v minimum for safety.
I worked for GE Oil & Gas until recently and saw what happens when you put 3000volts on 1000volt wire.
 
2500vdc at 1 amp

I guessed wrong one time and connected a meter rated for 1kv into a curcit running 2500vdc at 1 amp. Makes a big mess, and i'm glad I wasn't not grounded. I picked up parts of the meter for weeks, even the case was blown apart. I bought a HV probe the next day and if in not sure of the voltage it gets used. And the power supply that I shorted out did not even blow it's line fuse, just kept running like nothing had happened.
 
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<snip>I picked up parts of the meter for weeks, even the case was blown apart. <snip>

As exciting as that was you got off lucky.. :D And thanks for sharing that with fellow members, hopefully it will help someone avoid the same mistake with potentially even more catastrophic consequences.

@ OP
Have a look at tubelab's comments about HV safety and also his site for guidelines on how to do this stuff safely. Hopefully George will weigh in here at some point.

Extreme caution and careful research into the proper way to handle measurements at these sorts of voltages are paramount to personal survival. (Explosions, flying shrapnel, fire and electrocution are real hazards and may result in FATAL injury.) Having the proper equipment, and understanding how to use it safely is critical. I go so far as to avoid direct measurement of these voltage levels in my own designs. I use well characterized resistors in bleeder circuits that also provide a convenient measurement point with a known divider ratio - usually 1:3 or 1:4 so that I do not have to measure things directly.
 
@ the op - I am going to presume that you know what you are doing - if I'm wrong, Darwin will address the issue anyway.

To anyone else reading this thread and thinking that they might like to give it a go, bear in mind that once you are over about 700V electricity makes its own mind up often about where it will go. Flashovers are common and an air gap is no protection.

Variations as simple as a change in humidity can be life or death situations, and you will get NO warning. Nada, zip, nil, not a bean, nothing.

At 1kv, death is not a possibility, it is certain. If you have no experience or training in working at these voltages, then quite simply, don't. Your meter may be rated to 1kv, but your heart and central nervous system is not...
 
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