Re: Drive Relay with MOC3010?


"Laurie Forbes" <laforbes@xxxxxxxxx> schreef in bericht
news:BkmWf.15833$K11.7102@xxxxxxxxxxx
I'm building a motor controller that will be controlled by a PIC and have
some circuit examples wherein the PIC drives a MOC3010 optoisolator which
in turn is used to drive a triac. I'm wondering though, can the same
MOC3010 be used to directly drive a relay instead assuming the relay coil
current is within the 3010's output limit (which appears to be 100 ma).

TIA for any help..........

Laurie Forbes



Laurie,

According to the data*** the MOC3010 consists of a LED and a triac, the
latter intended to switch his big brother triac. These are typical AC
components that will not work with DC. AC-relays exists but trying to switch
one with the MOC3010 may blow it although not necessarily the first time.
Inductive components tend to have strange inrush currents depending highly
on the moment it is switched on relative to the 50/60Hz sinewave. So if you
want to use an AC-relay, control it with a cheap extra triac, not with the
MOC3010 triac itself. A DPDT relay seems a good and reliable way to switch
the direction of your drill motor but make sure the motor has been made to
turn in both directions. Otherwise you may run into mechanical or cooling
problems.

petrus bitbyter



.