Protection of my loads (batteries + equipment) from alternator

[dsswerwe]

I have an aftermarket additional alternator (24v, 100A) installed in vehicle without external regulator (don't know about internal regulator). I have found this alternator locally probably used alternator dismantle from used vehicle. Normally its voltage cutoff at 28.5 voltage, but we have observed that some of these alternators go up to 32v.

Our installation is like this

Alternator->battery + equipment. Alternator will give current to both simultaneously i-e batteries and equipment (according to their needs). I need protection for my equipment and batteries from alternator by overvoltage and over current which may heat up the alternator if max current is drawn by it from load.

How can I protect my loads (batteries + equipment)? If alternator get faulty and gives overvoltage or load draws max current? any controlling device which can fulfill my requirement?

 

[kellys_eye]

How can I protect my loads (batteries + equipment)? If alternator get faulty and gives overvoltage or load draws max current? any controlling device which can fulfill my requirement?

Fuses for over-current. In fact, fuses protect your CABLING and are essential.

Over-voltage shouldn't occur with the correct regulator on (or in) the alternator. If it hasn't got one you shouldn't be using the alternator for the purpose you currently are.

Individual equipment should have 'some' sort of protection anyway.

 

[dsswerwe]

Fuses for over-current. In fact, fuses protect your CABLING and are essential.

Over-voltage shouldn't occur with the correct regulator on (or in) the alternator. If it hasn't got one you shouldn't be using the alternator for the purpose you currently are.

Individual equipment should have 'some' sort of protection anyway.

which DC fuses would you recommend and also do you know any alternators which can be fitted in vehicles (universal fitting alternator). Is there any device which I can use with my existing alternator which can protect my load from over voltage and over current.

 

[danadak]

Load dump in vehicles :

https://www.ti.com/lit/an/snva681a/snva681a.pdf?ts=1689331020836&ref_url=https%253A%252F%252Fwww.google.com%252F

https://www.st.com/resource/en/application_note/an2689-protection-of-automotive-electronics-from-electrical-hazards-guidelines-for-design-and-component-selection-stmicroelectronics.pdf

https://www.infineon.com/dgdl/Infineon-AppNote_Short_Introduction_To-PROFET+24V-AN-v01_00-EN.pdf?fileId=5546d4625b62cd8a015baa99a3a21479

https://us.v-cdn.net/6030708/uploads/FileUpload/27/83834bb53d979002cca477431d065f.pdf

Regards, Dana.

 

[kellys_eye]

which DC fuses would you recommend

None. That's for you to decide. You could use automotive (I don't know your application) or even resettable fuses (circuit breakers) or power switches (on/off) that have circuit breakers built-in. Very few alternators use external regulation these days and are devices to be avoided due to their 'rarity').

(universal fitting alternator)

They all are..... they might have differing physical mounting arrangements but otherwise they all work on the same basic principles (built-in regulators). Check the manufacturers spec on them though as they have particular requirements for cooling and ratings for maximum/intermittent loads. Some have isolated negative (return) terminals (marine applications) etc.

Is there any device which I can use with my existing alternator which can protect my load from over voltage and over current

Again- fuses (over current). The over voltage issue is a non starter IF the installation is correct and the equipment it is powering is properly designed.

 

[crutschow]

If you really want over-voltage protection then you could use an SCR crowbar circuit, that shorts the alternator output and blows the fuse you have added (or opens an added breaker) if the voltage exceeds a preset value.

I can post such a circuit if you are interested in building one.
At what voltage would you want it to crowbar?

 

[Delta Prime]

I have something to contribute.
Get a voltage regulator controller, readily available off the shelf, basic function would be if the electrical system needs more power than the alternator can produce, then the battery is connected to the system & the battery will contribute the needed power, under equipment load the alternator RPM's must increase, with a 100amp alternator in my vehicle the alternator will not constantly be producing 100amps. When driving & with a brand new battery charged, the alternator produces only about 3amps of current.(No matter how powerful the alternator, the output is limited to what the system demands).

 

[danadak]

GE Scr Manual for crowbar circuits, section 8.

components :: ge :: 1972 GE SCR Manual 5ed : Free Download, Borrow, and Streaming : Internet Archive

From the bitsavers.org collectio n, a scanned-in computer-related document.components :: ge :: 1972 GE SCR Manual 5ed

archive.org

Regards, Dana.