Relay Switch

[austinhuntzinger]

Hello,
does anyone know what kind of relay switch i need to control a dc 12v 100 amp motor from printer lpt port pin d0-d7

 

[jsc]

A pretty heavy one. A relay capable of handling a 1.2 kw load will not be able to be driven directly by the computer output. You will need some sort of electronic relay driver or one or two smaller relays.

A great source for electronic parts in the US is Mouser Electronics:
http://it.mouser.com/search/default.aspx

They were recently bought by an Italian company so when you hit their site, to get the U.S. distributors, you need to select English language and USD currency.

Filtering for 100 amp contacts gives this:
http://it.mouser.com/Electromechanical/Relays-I-O-Modules/General-Purpose-Industrial-Relays/_/N-5g36?P=1z0x1d8

 

[austinhuntzinger]

ok maybe i dont need 100 amp i need to change things up a little what kind of relay would i use for this motor =... now i need to have two of these on my ROV im building
MODEL: MY1016 motor by Unite Motor Co. Ltd.
TYPE: Brush
VOLTAGE: 24 Volt DC
RATED SPEED: 2600-2850 RPM
RATED CURRENT: 13.5-13.7 Amp
SPROCKET: #25 Chain
OUTPUT: 250 Watts

 

[austinhuntzinger]

A pretty heavy one. A relay capable of handling a 1.2 kw load will not be able to be driven directly by the computer output. You will need some sort of electronic relay driver or one or two smaller relays.

A great source for electronic parts in the US is Mouser Electronics:
http://it.mouser.com/search/default.aspx

They were recently bought by an Italian company so when you hit their site, to get the U.S. distributors, you need to select English language and USD currency.

Filtering for 100 amp contacts gives this:
http://it.mouser.com/Electromechanical/Relays-I-O-Modules/General-Purpose-Industrial-Relays/_/N-5g36?P=1z0x1d8

_______________________________________________________
ok maybe i dont need 100 amp i need to change things up a little what kind of relay would i use for this motor =... now i need to have two of these on my ROV im building
MODEL: MY1016 motor by Unite Motor Co. Ltd.
TYPE: Brush
VOLTAGE: 24 Volt DC
RATED SPEED: 2600-2850 RPM
RATED CURRENT: 13.5-13.7 Amp
SPROCKET: #25 Chain
OUTPUT: 250 Watts

 

[americanbrian]

Ok so you need to consider a few things here...

What is the output voltage for the LPT port. I read it as 5V

What maximum current/power can be driven from the LPT port. I cannot find this info easily.

Assuming you can drive 200mw the appropriate relay for you would be something like this:

G5CA-1A-E DC5 Omron 15A 5Vdc coil

available from RS : order code: 508-2502

I am assuming that you are using this purely to switch the power to the motor. any auxiliary functions cannot be accomodated as the Relay has only one Normally Open contact.

you will obviously need two, one for each motor.

I am assuming this is a personal project rather than anything professional. These are cheap but rated to your task.

My main concern as mentioned is that you need to be able to drive the coil. generally the pins on a LPT would be for data, ie no significant loading. Good Luck.

BTW: thats is RS components in the UK. I think there is a USA one too, but maybe order code will be different. just google the manufacturer part number.

 

[austinhuntzinger]

Ok so you need to consider a few things here...

What is the output voltage for the LPT port. I read it as 5V

What maximum current/power can be driven from the LPT port. I cannot find this info easily.

Assuming you can drive 200mw the appropriate relay for you would be something like this:

G5CA-1A-E DC5 Omron 15A 5Vdc coil

available from RS : order code: 508-2502

I am assuming that you are using this purely to switch the power to the motor. any auxiliary functions cannot be accomodated as the Relay has only one Normally Open contact.

you will obviously need two, one for each motor.

I am assuming this is a personal project rather than anything professional. These are cheap but rated to your task.

My main concern as mentioned is that you need to be able to drive the coil. generally the pins on a LPT would be for data, ie no significant loading. Good Luck.

BTW: thats is RS components in the UK. I think there is a USA one too, but maybe order code will be different. just google the manufacturer part number.

ok i read somewhere on the internet there is something that could boost the lpt port amps and voltage that could power relays, but i dont know wich chip it is.

 

[austinhuntzinger]

Ok so you need to consider a few things here...

What is the output voltage for the LPT port. I read it as 5V

What maximum current/power can be driven from the LPT port. I cannot find this info easily.

Assuming you can drive 200mw the appropriate relay for you would be something like this:

G5CA-1A-E DC5 Omron 15A 5Vdc coil

available from RS : order code: 508-2502

I am assuming that you are using this purely to switch the power to the motor. any auxiliary functions cannot be accomodated as the Relay has only one Normally Open contact.

you will obviously need two, one for each motor.

I am assuming this is a personal project rather than anything professional. These are cheap but rated to your task.

My main concern as mentioned is that you need to be able to drive the coil. generally the pins on a LPT would be for data, ie no significant loading. Good Luck.

BTW: thats is RS components in the UK. I think there is a USA one too, but maybe order code will be different. just google the manufacturer part number.

what full proof method would you suggest i use to get the motor to work with lpt i have made the program to cotrol it i just dont have the required relay to power the motor and i cant find any specific information about the relay switch needed to use the lpt port, iknow that that lpt port has a masximum of 5v dc output but i dont know how many miliamps it outputs, i could imagine about 2 ma max i could think of, but i cant find a relay the would activate the coil mechinism to make the switch work, unless there is another chip or or something i could use to take the incomeing lpt port to the relay to increase its ma or voltage, would a capaciter do this job.?

 

[americanbrian]

Ironically you probably need another relay to switch the "power" relay. The root of the problem is that you are trying to use outputs that are really strictly data lines.

You would be better if you used a dedicated PLC (programmable logic controller).

However, that is not to say you can't use the existing ports. If you wire a SSR (solid state relay) they pull down very little amps usually. The output from that could then be used to switch the actual power relay.

I assume that you have a 24VDC supply as thats is what will drive the motor. I therefore suggest you use a line from that to actuate a 24VDC coil relay (through the SSR).

I hope you are only needing to control these two things because eventually if you keep adding controls to the LPT, you will end up costing more and more as well as complicating your wiring.

I was once a C&I Engineer on power systems (Gas Turbines). Trust me when I say that re-inventing stuff is just not worth it. The reason PLC's and SCADA exist is exactly for this type of thing. Use what suits the job best. Several PLC's have ethernet connectivity (so you can interface with your PC). you can probably pick up a cheap used one on ebay. Also programming them is really very easy to learn.