IVR vs Conventional (Wound) VR

It's less expensive since there is no extra case/packaging/wiring/attachment hardware required for an integral component.

External voltage regulators are an artifact of older generators and technology.

They work better and they last longer....

http://www.secondchancegarage.com/public/83.cfm

correct me if i have the wrong theory: IVR and conventional VR of the same VA rating basically would have the same desired output? the mechanic kept telling us to use IVR instead since it can deliver power compared to the wound vr, and basically, i deem it to be of wrong thinking...unless a higher VA rating for IVR will be used, right?

Separate voltage regulators were used when electrical requirements were low....that is no longer the case in most auto electrical systems...So you would need a VR that was designed to work with the electrical current needs and capabilities of your particular system...be it internal or external is of no consequence....it's the design that matters...

per say, the design was based on the voltage output level regardless of the VA rating...therefore, higher VA can compensate the power needs. the real problem here is the wound vr was not designed to cater the power needs when air conditioning system was installed. so to compensate this,i need to replace my old wound vr with a vr of higher VA rating. either ivr or another wound vr with higher VA rating will be used, and with the same design output.

I assume by integrated VR you mean transistorised, as opposed to wound (vibrating-contact) type. I've never heard of a wound regulator integrated into the alternator, but some early ones had an external transistorised regulator.

Do you mean you want to increase the output of your alternator? You can't do that by changing the regulator, whatever type. The maximum alternator field current (via the regulator) is determined by the resistance of the field winding, and happens when the battery voltage is low so the regulator is not doing anything, and is typically 3 - 4 amps. Most of the time the field current is much lower, due to regulator action. The regulator clearly must be designed to handle the field current, but I've never seen VA ratings quoted, or a regulator selected (at auto-electrician level) for a particular rating. The output of the alternator is determined by its construction, not by the regulator. If you want to find the maximum output, you can bypass the regulator with a length of wire (if you know what you're doing), rev the engine, and measure the amps. Ref #3, I don't agree with your mechanic.

If you want more amps you need to fit a bigger alternator, preferably a modern one with built-in regulator.

Ok if I understand you correctly, you have added A/C to your car and the output of the alternator is not sufficient....this has led to the failure of the voltage regulator...now you are proposing to change the voltage regulator for a higher rated unit....Well this won't work, you need more output from the alternator...with a VR to match...

"Most factory alternators are rated at 65 to 100 amps and are capable of handling a vehicle's basic accessories-headlights, gauges, fuel pumps, transmission, A/C, etc. While many alternators have a 10-percent to 15-percent power reserve to handle additional accessories, this is often insufficient capacity to power high end audio systems or other high-amperage items.

For example, a typical 500-watt stereo system draws upwards of 60 amps when cranked. A stock vehicle's electrical accessories draw an additional 60 amps total. To run 120 amps' worth of goodies with an 80-amp alternator, it will have to run at 100-percent capacity-and draw reserve power from the battery-with no cool-down time. The result is predictable-drastically reduced alternator life.

If you're looking for hard evidence that you need to upgrade your alternator, take a look at your voltmeter. When you are drawing reserve power from your battery, the voltmeter will read below 12.7 VDC. If your voltmeter spends a lot of time below that figure, you are surpassing the maximum capacity of your alternator."

"Selecting the right alternator comes down to figuring out your vehicle's total electrical load. The most accurate way to determine electrical load is with an ammeter. With the engine off and the battery charged, connect an ammeter in series with the battery's ground terminal. Switch each electrical component on and off, noting their amperage draws. Add up the total ammeter readings. Your alternator output should be 50 percent greater than that figure.

If you don't have an ammeter, you can estimate electrical load by checking the accessory fuses. The amp ratings will be slightly higher than the highest draw of each component , but the sum of all fuse ratings will give you a general idea of the vehicle's electrical load."

http://www.onallcylinders.com/2012/10/17/how-to-choose-an-alternator/

I don't think he said his VR has failed, though if his alternator is undersized for the new duty it could be working at high % output hence high field current for extended periods, which might shorten VR life. Could shorten the alternator life as well.

Does A/C impose a significant extra electrical load? I always thought it was mostly crankshaft power to drive the compressor, unless later compressors use an electric motor.

Your link lists a load of amp draws, but several eg horn, windows, seat adjustment are intermittent and OTT to include them.

Also says

A good-quality, high-amp alternator can also help you gain horsepower. While most alternators are only about 75-percent efficient (some power is lost in the form of heat and wind resistance from the cooling fins), a higher amp alternator will recover lost horsepower by allowing your electrical system to run at maximum voltage.

As the formula shows, this alternator doesn't take much horsepower to operate. And by supplying the proper voltage to your electrical/ignition system so it operates at peak efficiency, the alternator can actually help your engine produce more power-more power than it takes to operate the alternator itself.

That seems to me like overdoing the salesmanship. It comes close to an over-unity claim! The whole point of modern ignition systems I believe is they're less susceptible to reduced battery voltage, specially during cranking. I wonder if he's an advocate of electrolysis/hydrogen injection .

Well yes this is true if you have a capacitor discharge (CD) ignition system. Voltage is less critical and the spark remains the same....there are other systems though that it will make a big difference...such as High Energy Ignition (HEI) systems...

http://www.custom-car.us/ignition/voltage.aspx

Reading between the lines it appears that OP has added an aftermarket air conditioning system to an older vehicle and is finding that the lights are dimmer when the car is standing still.

Reduced alternator output is a common problem since the additional mechanical load of the compressor reduces the idle speed of the engine resulting in a lower output from the alternator. If this is in a vehicle driven primarily in the city then the lower idle speed during prolonged stop and go traffic, combined with the added electrical load of the compressor clutch and the now constantly running cooling fan, is causing the battery to lose charge faster than it can be recharged.

The first thing I would do is check the belt tension to make sure that new longer belt isn't slipping on the alternator pulley. If that doesn't cure the problem then make sure all your battery cables/connections are clean and tight since hidden corrosion/broken strands increase resistance and voltage drop. Next change the alternator pulley size so that the shaft turns faster thereby increasing its output. Some retrofit a/c kits also include a vacuum or electric idle kick-up unit to raise the idle when the compressor kicks in, make sure your installer didn't conveniently "forget" to install it.

If all that fails then it's time for a rebuilt higher power alternator that can fit in the same space as the old one. Changing the voltage regulator (unless faulty) won't do anything for you.

HEY, THIS IS A TECH FORUM, NOT 20 QUESTIONS.

Stop playing games with us and ask what you need. I have had 100 amp 12 volt mechanical voltage regulators, and 10 amp 12 volt intergrated regulators.

Start with year, make, model and engine. From there we can help guide you IF you want us to.

Here is something that should help you understand how a voltage regulator controls the alternator. You will also find out why you need to have a large enough alternator for your car. Since you added Air Conditioning, your current alternator does not produce enough power. Know that a 120A alternator will take 3-4 HP to operate. If you are already short on power, this will only make things worse.

I hope this helps:

http://www.madelectrical.com/electricaltech/howitworks.shtml

I have not seen an external electro-magnetic VR in years. Modern cars don't have a VR per se. The alternator output is controlled by the ECU. The ECU controls the field current, which controls the alternator output.

If you wanted to add an external VR, I don't think you can and it wouldn't do any good. Let me take that back; you could add one, but messing with the ECU isn't advised and most likely you'll cause yourself more grief.

Hello. Your words "Conventional (Wound) VR" to me suggest that you are referring to an electromechanical regulator. If that is the case there are many differences. Obvious advantages of IVR are reduced wiring,simplified electrical system, greater reliability and longer life. The electromechanical VR uses precious metal contacts which oxidize and stick shortening it's life. Accuracy and Stability of calibration is dependent not only upon design and materials but also upon the servicing of the mechanics/technicians in the close tolerance gap settings. Most external VR's sensed system voltage at the battery so that in an open or high resistance in the connection between battery and alternator caused an unregulated over voltage mode causing electrical system damage. IVR's of course sense at the alternator eliminating this problem. Another advantage of many IVR's is the use of Darlington type power amplifiers in the output circuits allowing higher field currents than the EMVRs. IVR's employing thermistors for temperature compensation have better voltage regulation at low temperatures saving light bulbs and electronics from over voltages.

Hope this helps.

IVRs of course sense at the alternator eliminating this problem.

Not always. The power to the field, via the regulator, comes from the 3 field diodes, but there are at least 3 options for sensing.

1 - from the field diodes.

2 - from the output diodes, internal to the alternator

3 - from the battery, via a lead from the battery to an additional connection on the alternator

Then there's the modern way, control via the car ECU. I'm not sure whether that still uses a regulator, but with the setpoint provided by the ECU (which could take account of ambient temperature etc), or whether it supplies the field directly (to give required output volts). If it's the latter, I don't see why the 3 field diodes could not be eliminated, giving a cheaper machine. The field supply would need to be switched off when the engine is stopped, but the ECU could easily do that.

I tried to find details on the internet, without much luck. Perhaps somebody on here knows?

I found something on the internet. No field diodes. Presumably the connections to the 2 phases switch off the regulator when engine stopped, to prevent draining the battery via the field. Thinking about it again, maybe 3 - 4 amps for the field coming directly from the ECU might not be practical.

I had two British sports cars with the mechanical regulator, worst electrical noise producers ever made. Having to clean the contact periodically along with the generator on each car the size of the starter motor makes the Alternator the most practical solution to power.

I could take the cover off the regulator, and by closing the contacts, cause the generator to "crank" the engine of my MG Midget.

I'll stay with the built in regulator on my boat and truck, 3 wire hook-up and simplicity of maintenance.

Now I wish they could make an alternator from my rice burner bike instead of the magneto with the dump the excess power overboard regulator - greatest fear is boiling the battery during a sustained high speed run (anything requiring 4200 rpm or greater).

I could take the cover off the regulator, and by closing the contacts, cause the generator to "crank" the engine of my MG Midget. I'd have liked to see that! Did it crank it the right way? My guess is it would go backwards (field current in normal direction, rotor current backwards) but I could be wrong.

Presumably you mean the cut-out contacts? Usually when they stick together, or if you inadvertently close them with the engine stopped (and the reverse current holds them closed), there's practically a short circuit through the rotor and things quickly get very hot. You have to start the engine sharpish or pull the contacts apart, likely getting a burnt thumb, but it's worth it.

If the fanbelt is off the dynamo would turn and (probably) the current fall, due to back-emf, but I'm surprised it has enough power to crank the engine. Clearly it does if you've seen it.

The generator was larger than the starter motor. The engine was only 1098cc, and the pulley on the generator was small enough to give it mechanical advantage.

I just love the British Sports Cars of that era, a lot of noise, the variability of whether it would run, and the small size. I had neighborhood kids get in and think it was a pedal car!

LOL!

Those old Triumphs, MG's, Sunbeams are really neat cars.

I have to agree with you on that. At one time I owned 2, Plymouth Crickets and a Hillman Husky.

It really depends on the type, age and make of the alternator as to what amperage you are getting at idle speed and at optimum rpm of the alternator.

It will also depend on the vehicles load as designed originally on the vehicle, so if you have additional loads installed the alternator may not be designed to handle the additional load. (Output V & A)

The regulator is limited to the maximum of the designed electrical voltage and current of the vehicle. so you need a regulator and alternator that can manage an average of the given maximum, that one uses, at any given time.

On IVR there are slightly less losses due to the efficient electronics, than on a wire wound regulator.

The regulator only controls the voltage, and (subject to what I said in #6) is the same for any size of alternator. The alternator design output current depends on the size.

Modern automotive alternators have evolved quite a bit over the past few years. Although the design of the alternator hasn't changed much, the control circuitry has.

The modern AVR is now embodied as a distributed control system, accepting inputs from the field, stator, battery, and the other computers in the vehicle (my Cruze even has a CT surrounding the negative cable). By knowing the battery parameters, its SOC (State of Charge) can be determined in real time.

With knowledge of the alternator's output parameters and the vehicle power loading profile, the ECM can compute whether the alternator, battery, or both should power the electrical load under its current ambient and operational conditions. In effect the AVR module is an actuator controlling the flow of field current as determined by the ECM.

after loosely "scanning this thread" and failed Googling on "automotive conventional VR" -- i guess the VR-s come with crater variety.

in specific - if the VR is shunting or braking one - you loose generator power when it´s engaged (performs a limiting action) - to correct this:

(( 0) you need approval to modif. the el. sys. ))

1) {[Gen->(Super capacitor*)]->VR->battery**}->VR->[Car´s consuming grid]

* or other NRG storing buffer (e.g. 1 or more extra batteries)

** obviously the ® battery** which is now a relict has more of a symbolic mening here

What on earth are you talking about? What do you think VR stands for?

He may be referring to virtual reality. It does not match the electrical classes I had taken.

And the final outcome in resolving your issue was.....?

Just like the movie........Gone with the wind.