1. I need low cost 5 pin, 12V relay with SPDT & in both NC & NO state current should be 30A or higher.

2. Any suggestions?

3. I have searched this relay, but it is costly, any cheaper part?:
http://www.parts-express.com/12-vdc-automotive-5-pin-relay-spdt-30-40a-bosch-type--330-073

 

hi,
I would say $2.38 for that relay is a good price, also Bosch is a quality product.
E

 

To Add End application: Will be switching main on or off depending upon some condition.
Input driving : 12V dc
Output control : 220V ac , 30A ac , 50Hz

 

hi,
I would check with the supplier, I do not think the relay contacts are rated at mains voltages at 30Amps.!
It appears to be designed for automotive switching of 12Volts DC
E

 

The Bosch contacts are rated for 14V (automotive application) so you can't use that. Plus, the one referenced is 'Rayex' not real Bosch.

Take a look at TE Connectivity (formerly Potter and Brumfield) T92 and T9x. They are very reasonably priced for what they can do. There are also cheap Chinese knockoffs of the more popular ones that hardly ever melt in use.
Schrack is another good source but it looks like they are sourced by TE now - at least in the US.
Stay away from Hasco.

Good luck.

 

Also automotive types do no necessarily have the insulation rating for 230vac use. typically this type of application uses a contactor or other power relay such as P&B PRD series to also handle the current.
Max.

 

I have a bucket full of the 5 pin relays with 12 and 24 volt coils. Some are labeled 30 amps at 30 VDC others are rated 30 amps 250 VAC and the parts form one are identical to the other with the matching brands.

The only difference between them is what is printed on their caps.

I would bet my bucket of relays that if I took a pair of 30 volt DC rated and a 250 VAC rated units and put them side by side without their caps on and took a picture no one here could tell me which was which based on their internal components.

 

The size of the contact points, I think would be bigger with the 30 amp AC version.
The metal composition of the points also differs between AC and DC.
I would think using an AC relay on high power DC is more likely to weld the points than the other way around. Due to DC current never passing through 0 volts. DC current is continuous. SO DC contact points have to work with bigger make and break arcs.

 

I would think using an AC relay on high power DC is more likely to weld the points than the other way around. Due to DC current never passing through 0 volts. DC current is continuous. SO DC contact points have to work with bigger make and break arcs.

For high current versions there are also methods employed to extinguish the arc, permanent magnetic or coil wound arc blow-out.
I have seen a plasma arc form across a AC relay contacts when high current DC switching was attempted, the arc sustains enough to retain current to the switched load.
Max.

 

For high current versions there are also methods employed to extinguish the arc, permanent magnetic or coil wound arc blow-out.
I have seen a plasma arc form across a AC relay contacts when high current DC switching was attempted, the arc sustains enough to retain current to the switched load.
Max.

I recall reading years ago car makers wished to go to 48vdc to save on wiring-copper costs. But the switches and relays kept failing and they could not affordably engineer the change.

 

I recall reading years ago car makers wished to go to 48vdc to save on wiring-copper costs. But the switches and relays kept failing and they could not affordably engineer the change.

Now there is no large conductor bundles, a signal bus system is used and local electronic control is used via OBD-11 etc.
Things like blower motor and window motors are local PWM.
Max.

 

currently i am using 2 relays, didn't find single relay according to my specs

 

Consider a test room in which household appliances are run (like fan , tubelight , bulb or any other household appliance)
Have to switch between main & generator depending upon certain input criteria.

 

@vn2nan thanks 4 response

 

35 amp AC rated, and comes with various voltage ratings on coils.
http://relays.struthers-dunn.com/Asset/PM_Series_Motor.pdf

4 poles, so it is 4pole double throw. Accepts 2 different source inputs like gen or main and sends to one output. Each point is good for 35 amp, so you can gang together two and get 70 amps.

I have one and run the coil on 15vdc off a wal wart. Better pull in of the relay especially if you get a voltage drop, the walwart keeps the volts to the coil up higher.

 

Yes, these are nice relays.
you might get something new or used cheaper off ebay if you want it cheaper.
http://www.ebay.com/sch/i.html?_fro....m570.l1313.TR0.TRC0.H0&_nkw=PM-17AY&_sacat=0

Over the years, several companies have made this style relay. I found they are all heavy duty robust construction. Some the screws are inexplicably too short, so may need to get some longer ones. They are same thread as an outlet, but you need to grind the screw ends clean of the swedged ends.