03-24-2009 12:19 PM
I am trying to connect the FP-RLY-420 module to an output which has more than 100A and more than 800 Volts, both DC and AC. How do I do it? Since FP-RLY-420 has max 3A and 35VDC, 250VAC. What I need, to complish this task?
03-24-2009 07:03 PM
A heavy duty motor contactor. Something like this http://web4.automationdirect.com/adc/Shopping/Catalog/Motor_Controls/Fuji_Contactors_-z-_Overloads/1...
However the 800 Volts may be a hangup. Most normal motor contactors are based on interrupting a 480VAC motor. I don't know if these would have the specifications needed to interrupt 800V.
What is it you are trying to control?
03-25-2009 11:04 AM
RavensFan:
Do you know why contactors are typically specified for AC or DC loads? Thumbing through Allied they seem to be calssified as one or the other.
shan-3:
If you do go with a contactor, I would suggest putting it in a secure enclosure and make you you use one that is safely rated for your voltages and currents. These are lethal voltage levels.
-AK2DM
03-25-2009 11:10 AM
03-25-2009 11:11 AM
There are two outputs, each ouput consists of 200 A, 800V DC or AC, I am trying to swithc or toggle the outputs.
03-25-2009 01:36 PM - edited 03-25-2009 01:37 PM
AnalogKid2DigitalMan wrote:RavensFan:
Do you know why contactors are typically specified for AC or DC loads? Thumbing through Allied they seem to be calssified as one or the other.
-AK2DM
I don't know. Do you have a catalog page number or a part number that shows such a difference? I just skimmed through the catalog and I can't find an example of that. I know for the coil you would have either AC or DC current driving the coil. But I can't think of a reason why the load you are interrupting would matter whether it was AC or DC. Of course the current would matter. Perhaps it deals with peak current vs. RMS current on AC vs. a continuous current on DC. But that is still current. Perhaps it has to do with voltage interruption causing an arc in AC that may not be present in DC because AC voltage is measured in RMS, but the peak voltage would be higher.
shan-3 wrote:
There are 2 outputs, each output terminal has 200A and 800V either DC or AC, I am trying to turn ON and OFF the output by using the FP-RLY-420 module
That didn't add much information. Two outputs from what? What are they going to? What is the device you are trying to turn on and off and why? As AnalogKid said, these are deadly voltages and currents. I would highly recommend you talk to an Electrical Engineer about what you are trying to do before you do it.
03-25-2009 02:06 PM
Ravens Fan,
Big difference between AC and DC load on a contactor when it comes to arcing between contacts and contactor life. If enough voltage potential is present between two contacts as they open, then an arc will form. This arc will last as long as there is enough potential to overcome the physical gap between contacts. With DC the potential remains constant and the gap typically needs to be larger before the arc is extinguished. With AC, the zero crossings tend to help extinguish the arc with a smaller gap.
03-25-2009 02:21 PM
RavensFan and WayneC:
Thanks for the explanation, my thoughts were along those line. In the Allied 2008 Catalog, pg1159 has AC, pgs1160-61 have various DC. Contact ratings are for AC or DC only.
-AK2DM
Now back to our previous program....