I am in the process of getting a new Megohm meter and cannot decide if I want a digital or a hand crank. I do currently have a hand crank but not sure if I like the digital. I hear rumors they are not as accurate. Any suggestions would be appreciated. Thank you.
Megohm meter
- Thread starter rockman33
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kwired
Electron manager
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- NE Nebraska
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- EC
What is your intended use?
If you are primarily performing go/no go insulation testing I wouldn't recommend spending the money on more expensive units.
If you are mostly taking preventative maintenance measurements you need to know more details on the units you are considering, and know what features may be of benefit to you.
I mostly use mine for go/no go testing and have a rather inexpensive analog meter unit. I rarely even look at the reading, if you hit the test object with a high voltage and the meter moves more then 2/3 of it's movement, it is an obvious no go, If it just jumps a little and settles at less then 1/4 of the movement, it is a go.
K8MHZ
Senior Member
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- Electrician
They still sell hand crank meggers?
kwired
Electron manager
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- NE Nebraska
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- EC
Found this one pretty quick, sure there are probably others.
add: searched that site for term hand crank and came up with many hits
K8MHZ
Senior Member
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- Electrician
Wow. For some reason I just thought it was outdated technology.
kwired
Electron manager
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- NE Nebraska
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- EC
So is the incandescent lamp, but there are still many around
K8MHZ
Senior Member
- Occupation
- Electrician
So is the incandescent lamp, but there are still many around
Same with Morse Code keys. I have a couple. I also have a crank type meggy meter. What surprised me wasn't so much they could still be had, but how popular they still are.
I think I am down to 4 incandescents at my house. Eventually it will be one because I don't foresee an LED for the inside of my gas oven any time soon.
There are several in my vehicles.
K8MHZ
Senior Member
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- Electrician
Can you get an adapter for a crank type megger so you can power it with a cordless drill?
kwired
Electron manager
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- NE Nebraska
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- EC
Why don't they go back to hand cranks for automobiles in case of dead battery? Many of todays engines probably don't crank that hard, unfortunately you still need enough battery to power the electronic controls systems or it won't start anyway.
K8MHZ
Senior Member
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- Electrician
Really? I'd like to see the man that could hand crank start a modern 3.0L or so engine. It takes about 90 amps at 12 volts to spin a modern engine. That's about the same as a 1 1/2 hp engine.
kwired
Electron manager
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- NE Nebraska
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- EC
Question is how much power is needed to spin it enough that it can start, not how much is ideal. Even a small yard tractor will use more power with electric starter then what we might exert if using a pull cord to start the same engine, but the electric starter maybe does get it started quicker most of the time.
With today's electronic fuel injection, all one may need is fuel injection and spark at the right instant and need very little cranking, where as with old carburetor fuel delivery you do need some cranking just to draw the fuel into the cylinder. And the size of the lever of the crank handle makes a difference on how much the applied force gets multiplied.
K8MHZ
Senior Member
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- Electrician
Assuming the average person could hand start a modern engine, which I doubt very much, where would you put the hole for the lever?
kwired
Electron manager
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Big wind up knob right out the top like a toy might have especially on some of the smaller cars out there.
kwired
Electron manager
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- NE Nebraska
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- EC
Want other options, how about a device you pull out and shake like those flashlights you charge by shaking them, except you are charging the dead car battery
Don't tell the consumer how long it may take shaking that thing before enough energy was accumulated to start their car though.
Don't tell the consumer how long it may take shaking that thing before enough energy was accumulated to start their car though.
Fulthrotl
~Autocorrect is My Worst Enema.~
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- E
Big wind up knob right out the top like a toy might have especially on some of the smaller cars out there.
only on priuses.....
I'd go for hand cranked. You get feedback by how hard it is to crank.
It would be easy
the starter has a small pinion turning a large gear (flywheel)
say starter spins at 10000 and reduces to 500 20:1
T = 5252/10000 x 1.5 = 0.75 lb ft
at fw x 20 = 15 lb ft
put a 1 ft long hand crank on the engine crank and 15 lbs of force would do it
throw a pinion on the hand crank and a gear on the crank, onlt 3:1 and only 5 lbs on the hand crank is required
the issue is speed
but with modern engine controls starting is easier and smoother
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
A benefit of hand cranked, especially if in the field, is no dead batteries. On a couple of occasions I was present at startups where the motor supplier technician showed up to megger the motors and had dead batteries, I went to the car and got out my hand crank version to save everyone from having to wait.
Your hand will always be there for you and ready to do what you need. <insert favorite related joke here>
Your hand will always be there for you and ready to do what you need. <insert favorite related joke here>
Dzboyce
Senior Member
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- Royal City, WA
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- Washington 03 Electrician & plumber
I've only used hand cranked meggers. I got a Biddle that I've had for 25 or more years. A military surplus one that I've had almost that long. I bought a chinese one on Amazon a couple of months ago for one of my helpers. That $30 Chinese one works just fine for go/no go work so far.
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