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Old 29-07-2010, 14:15   #16
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G'day, mates. I use both a Sears clamp type for more precise work and believe it or not, have used the same cheap $3 multimeter for over 12 years. I use the cheap one for most of the routine electrical measurements and can always calibrate it against the Sears. Cheers.
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Old 29-07-2010, 14:20   #17
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What matauwhi & hellosailor said, about cheaper meters being edequate for many purposes, applies to those who have to ask "what meter".
Others, who point out the limitations of cheaper meters, are technically correct.
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Old 29-07-2010, 16:21   #18
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Bill, there's something funny going on with the Mastech. Amazon shows them unavailable right now, another online store shows them at $55 available internationally--but with no "add to cart" link. One picture shows it gray with red trim, another shows it bright yellow. Others show it new or used for $100-120 and vice versa.

More than one of these was built and exists, right? <G>
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Old 29-07-2010, 18:36   #19
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Over the years I have had cheap meters go out but never a Fluke. Flukes either get stolen or lost. I think the extra money for a professional grade meter is worthwhile.

There are clamp attachments for some meters which then allow you to measure over 10 amps...or better yet, buy a clamp ammeter as well.
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Old 29-07-2010, 19:13   #20
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Originally Posted by hellosailor View Post
Bill, there's something funny going on with the Mastech. Amazon shows them unavailable right now, another online store shows them at $55 available internationally--but with no "add to cart" link. One picture shows it gray with red trim, another shows it bright yellow. Others show it new or used for $100-120 and vice versa.

More than one of these was built and exists, right? <G>
Yeah...there are lots of models and prices out there. Apparently, according to Mastec's current website, the MS2138 is the red/gray model, while the MS2138R is the yellow model.

http://www.p-mastech.com/products/cat05.html

The MS2138 is available online from Hong Kong with free shipping for $78.

Egad...I just looked at mine. It's the MS2108, not the 2138, and it's green and yellow. Amazon has them for $149. I bought mine a year ago for under $100.

I've got several pieces of MASTEC gear....nice stuff for the price.

Bill
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Old 29-07-2010, 19:54   #21
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I do agree with others that big bucks are not needed for a meter. Further, I personally would not spend extra for a waterproof meter. Too many bucks involved and they are clumsy, I recommend purchasing 2 inexpensive meters in the $50-75 range.

There is one feature that folks overlook in a meter that should be considered. That is the ability to read frequency. Yes, generator waveforms are rich in harmonics that might corrupt a frequency reading but sometimes just getting close is important.

Frequency settings are important on generators is one operates a microwave oven or one of the old ferroresonant chargers. Both of those items use transformers (with a capacitor) that is very, very frequency sensitive. The ferro charger outputs a sloppy waveform that is somewhat constant in voltage over an input voltage of +/- 20% or so and hence called a constant voltage transformer. Microwaves use similar designs but are configured for constant current usage.
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Old 29-07-2010, 20:18   #22
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I think we need to know your capabilities to give you some advice on a meter.

No sense buying a $300 meter if all the symbols on it look like a foreign language to you. If you just want to do simple voltage checks and check for small amperage draws a 10amp auto range $25 meter will serve you just fine.
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Old 29-07-2010, 22:22   #23
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If you wish to accurately measure small currents a clamp on is not the tool to have. I would go with a direct read meter capable of reading up to five or ten amps or so.

I use a ¼ ohm precision resistor and my Fluke to make delicate current measurements. Great for determining current draw on LED’s, fluorescent lights, instrumentation, etc.

I think just about any of the modern solid-state meters are amazingly good, have little loading effect (ohms per volt) and seem to be pretty tough. My old Fluke 10, is now obsolete but has done 20 years of hard service in much more arduous conditions than a sailboat and is still going strong, but no parts available.

I have a little radio shack meter a little bigger than a business card on the boat, just in case the Fluke is not available. It has been there for years now and works great, still running on original battery. Only complaint is the short leads make some troubleshooting tough, but you should have a couple of jumpers made from good test lead wire with nice little alligator clips no matter what you use as a meter.

If you need to measure big currents get a dedicated amp clamp.

Most of the newer digitals are auto ranging and this can confuse anybody when you are hunting for a result, especially on ohms scale. When it comes up .888 does it clearly tell you that’s ohms or is it K-ohms? You will need to get some experience with the meter before you learn to trust it on auto-ranging scales. Don’t loose the book either!

I agree with foggysail on being able to check frequency. A nice plus if it does that. Your meter does not absolutely have to measure the inverter output with accuracy. For years I checked the output on a large inverter with my Fluke 10 and if it measured 91 volts AC I knew the output was perfect and actually acted like 120 volts of true AC.

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Old 30-07-2010, 05:31   #24
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... I use a ¼ ohm precision resistor and my Fluke to make delicate current measurements. Great for determining current draw on LED’s, fluorescent lights, instrumentation, etc...
Utilizing a known shunt resister, and measuring the Voltage Drop accross it; then calculating current by Ohms Law (Amps = Volts ÷ Ohms) is not generally practicable for in situ troubleshooting of circuits and/or components.
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Old 30-07-2010, 05:43   #25
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Meters vary but unless being very nit picky it won't matter much.

BTW the Mastech meter pictured, MS-2108, DOES NOT capture DC in-rush even though the lit claims "in-rush capability"... Live and learn. My Fluke BTW agrees most closely with the Mastech & Sperry. The meter on the right was bought at Wal*Mart one day when I forgot my meter. About $20.00, it's now my boat meter.

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Old 30-07-2010, 07:01   #26
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To measure DC current, you need a direct read meter or a shunt system or a special AC/DC clamp. Most clamps are AC only. The AC / DC clamp Fluke unit I use has it's own battery and zero point adjustment. It's probably not too good for small currents either.

Have used a Fluke 87 III for 30+ years and have a cheaper/smaller Fluke on the boat.

If all you want is a yes / no answer, any meter will do.
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Old 30-07-2010, 08:04   #27
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I use a Fluke 179 with a Fluke i410 clamp on addition, which plugs into the 179 with a 1mV/A output. Got them both off eBay and feel I got my money's worth. Wanted something I could depend on before I set out full time.
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Old 30-07-2010, 08:16   #28
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Gord,

You all sorta right.

The typical current check is used to balance loads in 120/240 systems or 3 phase systems, check inrush current, check motor load or prime mover output in amps. All best done with the amp clamp, which utilizes a built in current transformer and does not physically break into the circuit.

The shunt is not used in most troubleshooting, but with the exception of the above, the ammeter is seldom used for troubleshooting, especially the trouble shooting of most of the circuits found on a smaller sailboat.

Any meter that breaks the circuit and inserts the meter in the circuit is using an internal shunt. The shunt being external to the meter is doing the same thing but not inserting the meter into the circuit, only measuring the voltage drop across the shunt resistor.

Mainsail: I wish I had a meter that was that pretty. My tools look more work conditioned, I guess.

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