60A fuse.

I guess you're asking, "how can I prevent the delivery of more than 60 amps to a load by regulation," or that you want to test a 12 volt source by placing a load that will require 60 amps, in which case, I can answer either. But if that's not what you're asking, I would appreciate a little more detail.

As more load is added, the requirement is not to exceed and maintain 60 A.

If more load is added, and it is controlled to deliver no more than 60 A, then the voltage must be lowered. If lower voltage is acceptable, then it can be done by sensing the DC current (a couple of different types are available) and controlling a transistor of a variety of types to limit the current. It can also be designed to alert the user when the current is being limited. There are a few other things that can be done, such as shutting down, shedding other loads, etc.

Is a lower voltage than 12 V acceptable? If so, I can provide a circuit design, but it's such a pain in the butt for me to insert a drawing that I won't before I know that it's acceptable.

A 60 amp automobile alternator with internal regulator is designed to do just that.

ALTERNATOR. 12V, 60 AMPS. 14 VOLT, SIMPLE 2 WIRE HOOKUP

Item # 90502S ALL
Fits Chevrolet Cars and Trucks
Weighs 11lbs.

Alternators

12v-60 amp, 14v internally regulated, simple two wire hookup, replace any 12v generator, comes with D.A. plug, new

This part fits All Chevrolet Cars and Trucks

I don't think this could be done with passive regulation - a short of 60A at 12V is 700W, a lot of heat to get rid of. You would need a switching regulator. Look up '12V 60A DC-DC converter' and you will find various models that produce 13.8V from 10-15V input for example http://www.powerstream.com/dc2.htm. This seems to be only 60A peak rated though. Do you really need to limit the current (drop the output voltage)? It might be cheaper to use some sort of relay that will trip out at 60A...

If it's an inductive load or at least it has a significant inductive component you can use a switching regulator in series with the load.

If by "DC plant" you mean the vehicle's alternator, then this function is built into every alternator: the regulator will reduce current to the field to limit output to (typically) 14.5 volts and the alternator's rated amperage.

If you want to limit the amperage to a device powered from the vehicle's system so that the device will draw no more than 60 amps, then the first approach would be to design the device so that it does not draw more than 60 amps. A second approach would be to regulate the current to the device via pulse width modulation (a chopper). If you want to buy something off-the-shelf that does this, a controller for a small electric vehicle (an electric scooter) would do the trick (although it probably offers more capability than you need.)

Dear Guest,

Alternator regulators do not have any form of current or temperature limiting function. The current limit on an alternator is the winding's ability to generate the power. A short circuit cell in a battery can and does cause alternators to burn out as the regulator will always be on full field. If the revs are high enough the alternator will kep on producing more amps until either the electrolyte boils out of the remaining cells, thus reducing load, or the windings or diodes pack up.

regards

Chas

Why do you need to limit to 60A? Most starter batteries can supply >500A, albeit only for a brief time. Use a thermal breaker at the cables capacity. It will allow short periods of overloads without any risk to the cable or battery.

If you are more specific and you will get better answers.

regards

Chas