Proper Control Schematic - Switch Contacts
Proper Control Schematic - Switch Contacts
(OP)
What is the proper way to show Control Switch contacts on DC Control schematics?
Is it best to:
1) show all contacts as a simple open contact symbol, having a contact development show which contacts are closed during different switch positions, labeling next to the contact what state the switch is in when the contact closes
2) show the contacts in their typical position (eg. typically reclose is turned ON therfor this contact is tyipically open) labeling that typical position next to the contact....
|
= 79CO (ON)
|
where...
79CO - (reclose on/off) switch
(ON) - Indicates the switch is in the on position, allowing this contact to be open
3) Other?
It seems like every drawing done here is different, so I was just curious to see what is done typically in the utility industry.
Sorry for this elementary question. I hope I worded it correctly. Thanks for helping a newbie.
Is it best to:
1) show all contacts as a simple open contact symbol, having a contact development show which contacts are closed during different switch positions, labeling next to the contact what state the switch is in when the contact closes
2) show the contacts in their typical position (eg. typically reclose is turned ON therfor this contact is tyipically open) labeling that typical position next to the contact....
|
= 79CO (ON)
|
where...
79CO - (reclose on/off) switch
(ON) - Indicates the switch is in the on position, allowing this contact to be open
3) Other?
It seems like every drawing done here is different, so I was just curious to see what is done typically in the utility industry.
Sorry for this elementary question. I hope I worded it correctly. Thanks for helping a newbie.






RE: Proper Control Schematic - Switch Contacts
RE: Proper Control Schematic - Switch Contacts
Manual selector switches that include an "off" position should be shown in the "off" position. Those that don't have an "off" position (such as "heat/cool") may be shown however you'd like, but be consistent and add notes to anything vague or ambiguous.
Good on ya,
Goober Dave
RE: Proper Control Schematic - Switch Contacts
The traditional way to put these switches on a drawing is with a table.
RE: Proper Control Schematic - Switch Contacts
An entry identifying the use helps also - "Block Close", "Inhibit Remote" etc.