Will an 24V AC contactor work with a 24 V DC signal

katratzi said:
It may function for a short time, but as Peter said it will get very warm very quickly.

Theory there is, with AC the stated peak voltage only occurs twice for a fraction of the cycle. With DC, the peak voltage is applied all the time causing the coil to overheat, then eventually burn out.
 
In practice it welds all 14 of the things shut which then draws a pretty heavy amp load on the system. But no worries, no one was hurt.

Thanks again for the quality answer guys.
 
In an AC device with a coil and iron core there is inductive reactance that creates the necessary "impedance" (reactive resistance) in addition to the resistance of the wire to continuously limit the current. A DC device has inductive reactance only with the initial turn-on that limits the in-rush current and after that is dependant only on the resistance of the wire in the coil to limit the current.
 
For DC (at t> 0)
I=V/R

For AC (at t>0)
I=V/(Z+R)

Z is inductive reactance at given frequency.

So providing a voltage of same magnitude but of the type DC(frequency=0) will result in burn out of coil.
 
Last edited:
ryanweber101 said:
In practice it welds all 14 of the things shut which then draws a pretty heavy amp load on the system. But no worries, no one was hurt.

Thanks again for the quality answer guys.

Should have hung around your computer for a few more minutes before heading back to the shop floor. :whistle:
 
ryanweber101 said:
In practice it welds all 14 of the things shut which then draws a pretty heavy amp load on the system. But no worries, no one was hurt.

Thanks again for the quality answer guys.

Why would you ever try applying a power that is specifically not listed on the operating spec?
 

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