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Relays now triggering! Still need an Electrical Engineer

Akilae729Akilae729 Registered User regular
edited December 2010 in Help / Advice Forum
For a research project in need to control a three phase motor with a solid state motor reversing relay.

Specifically one of these

Struthers-Dunn 645RT Series

645RT_Series.JPG

I've got my motor wired up as shown on the wiring diagram (including the two included varistors in the R1 and R2 positions.

imageresizer?image=645RT_Wiring_Diagram.jpg&quality=75&size=100&IsRemote=False

I also have a 24V DC Voltage currently across the forward control input. The 24 volts is supplied by a 5A independent power supply.

However, I can't get it to trigger and switch my motor on.

Do any of you have experience with anything like this / is there something I'm missing?

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Akilae729 on

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    Dunadan019Dunadan019 Registered User regular
    edited December 2010
    the maximum input on the specs says 80 mA.... 5A may be too much.

    Dunadan019 on
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    ecco the dolphinecco the dolphin Registered User regular
    edited December 2010
    Not sure if there are internal pulldowns, but just in case there aren't, have you attached a pulldown resistor between pins 7 and 8?
    Dunadan019 wrote: »
    the maximum input on the specs says 80 mA.... 5A may be too much.

    Nah, that probably means 5A max. Unless he is driving it from a current source, which would be really really really weird. :rotate:

    ecco the dolphin on
    Penny Arcade Developers at PADev.net.
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    Akilae729Akilae729 Registered User regular
    edited December 2010
    Not sure if there are internal pulldowns, but just in case there aren't, have you attached a pulldown resistor between pins 7 and 8?
    Dunadan019 wrote: »
    the maximum input on the specs says 80 mA.... 5A may be too much.

    Nah, that probably means 5A max. Unless he is driving it from a current source, which would be really really really weird. :rotate:

    I tried to put a resistor in series with my control line to force a current of ~48mA. Still no effect.

    Akilae729 on
    signaturebighe7.jpg
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    Akilae729Akilae729 Registered User regular
    edited December 2010
    So the relays are triggering now, HOWEVER, the forward control and the reverse control will not work if the two grounds are wired together.

    I'm using a TTL board with a single ground and to get the controls to work, i need to physically disconnect the ground to the opposite control.

    Is there a way to isolate these grounds electronically?

    Akilae729 on
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