How to tell a bad motor?

[Howard]

Other then a completely dead motor does anyone know how to tell if a motor is bad? I have one that revs extremely high at WOT (to high) Is this an indication of a bad motor also?

[m4a1usr]

Other then a completely dead motor does anyone know how to tell if a motor is bad? I have one that revs extremely high at WOT (to high) Is this an indication of a bad motor also?

Having a motor spin up beyond what you believe to be correct for its limits would require more information. It would be obvious to us if you stated that its a 4500kv motor and you were using a 4S for power. But to answer your question about how to tell is a motor is bad you have several options. One,.........you could spin the motor, chucked in a drill and spin it up, then measure the voltage on all three legs. Each of the three should measure an equal voltage. If you saw a large difference than the motor probably is bad. Second,.....Measure the resistance between the legs and than to the case. Unfortunately this requires you have a very high precision volt meter. Most folks are not going to own one. A fluke mod77 is not going to do it.

John

[properchopper]

Having a motor spin up beyond what you believe to be correct for its limits would require more information. It would be obvious to us if you stated that its a 4500kv motor and you were using a 4S for power. But to answer your question about how to tell is a motor is bad you have several options. One,.........you could spin the motor, chucked in a drill and spin it up, then measure the voltage on all three legs. Each of the three should measure an equal voltage. If you saw a large difference than the motor probably is bad. Second,.....Measure the resistance between the legs and than to the case. Unfortunately this requires you have a very high precision volt meter. Most folks are not going to own one. A fluke mod77 is not going to do it.

John

Man, I was good to go to test a few "suspicious" motors until I read the last sentence. My Fluke 77 is now hiding under the bed in shame :crying:

[JIM MARCUM]

Tony, my Fluke 77 wants a date With yours. Can it come out & play?

[m4a1usr]

Man, I was good to go to test a few "suspicious" motors until I read the last sentence. My Fluke 77 is now hiding under the bed in shame :crying:

Dont fret Tony. I dont have one either. My bench meter is an old Fluke 8020. But I have many from work of the "right" ones to use. My favorite is a HP 34401 but the HP 3458 is better. Problem in its massive. Like the size of a DVD player. Thank goodness I dont have to test motors often!

John

[G1ST]

I'm feeling "Fluke envy"
My Radio Shack DMM is on the outside looking in.
Greg

[properchopper]

I'm feeling "Fluke envy"
My Radio Shack DMM is on the outside looking in.
Greg

Bro, don't feel bad; back in my "salad days" the only way I could test a brushed motor was to plug a wire into each nostril and comb my beard real fast :lol:

[G1ST]

Tony, That is a visual that is going to be tough to shake.

[G1ST]

It there a test that I can perform with a standard multimeter that will tell me if a motor is going bad?

[properchopper]

It there a test that I can perform with a standard multimeter that will tell me if a motor is going bad?

step 1 : Attach meter leads to any two motor wires

step 2 : place nostril on motor endbell

step 3: inhale deeply through nose

step 4 : if memory of last encounter with nasty hooker is awakened, reject motor and flush nose (and memory) with good single-malt beveridge.

[G1ST]

step 1 : Attach meter leads to any two motor wires

step 2 : place nostril on motor endbell

step 3: inhale deeply through nose

step 4 : if memory of last encounter with nasty hooker is awakened, reject motor and flush nose (and memory) with good single-malt beveridge.


I gotta party with you!