Master contactor question

On Oct 29, 10:35 am, brian whatcott wrote:
jan olieslagers wrote:
schreef:
The large ST35 and ST36 are the only continuous duty units rated at
14-16 ohms. All the smaller ones are 16-25 ohms.

Isn't there a difference in resistance betwen the active state and the
passive? I feel some people have determined coil resistance by measuring
with a cheapo multimemer - this uses a small battery, the ensueing
measurement will reflect the inactive state. Better would be to activate
with a battery (or better still, a stable 12V reference) and measure the
current.

Yes there is a difference in resistance with temperature for most metals.

But I certainly hope you couldn't spot the difference with any ease.
This is not a filament whose resistance can double (or more) at
operating temp.

Brian W

And it isn't operating on AC, where inductive resistance would reduce
the current flow. If the ohmmeter says 14 ohms, then it'll draw one
amp at 14 volts. That might decrease a small amount as it gets hot,
but not much.

Dan