# Questions tagged [alternator]

Electrical generators that produce alternate current.

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### Alternator capacity selection [closed]

Do we need to change the alternator capacity if we are using an electro hydraulic steering system instead of a Hydraulic Steering System?
801 views

### I am running 10 kVA alternator from 10 hp motor and need some technical clarification

Here is my equipment: I am using solar controller to run motor which runs alternator which generates electricity and which is used for my house 🏡 requirements. 10 kVA single phase 220 V, 50 Hz @ ...
1 vote
34 views

### Calculate alternator power from open voltage and short current

A 3-phase BLDC motor, used as an alternator, outputs 3V open-circuit and 5A short-circuit at a given RPM. How can you calculate or at least estimate its useful power at that RPM if we connect it to a ...
100 views

### Questions About My Perpetual Motion Idea [closed]

Before you read any of this, this is just an idea. I am not an electrician, I am not a contractor, I am not a physicist, or anything like that. I just have an idea that i think could possibly work. I ...
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1 vote
116 views

### Is a high-amp car alternator three phase or single phase power? (12 V, 150 A machine)

I am in mechanical engineering, and have only worked with three-phase power. I modeled a 12V, 150A car alternator as a three-phase electrical machine simply based on when I look up what most ...
1 vote
47 views

### Is voltage to frequency ratio of a permanent magnet alternator constant in different speeds?

We have a permanent magnet alternator. I want to know if we change the speed of rotation, are the output voltage and frequency increased by same proportion? Is V/f ratio constant in different RPMs?
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1 vote
73 views

### Permanent magnet alternator: what happens when windings get shorted together for voltage regulation?

Here is a typical scheme for a permanent magnet 3 phase alternator as found on many motorcycles and recreational vehicles, with rectification to DC via a diode bridge and subsequent voltage regulation ...
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140 views

### What wiring diagram symbol is shown in this image?

What wiring diagram symbol is shown in this image? This is from my automotive electrical class.
32 views

### Engine instrument panel with duplicate Charge light, one incandescent and the other LED [closed]

I have an engine in a boat. The ignition on switch, start, and heat are on a panel on the navigation desk. There is also a power LED, incandescent charge, and led oil light. All the engine instruments ...
178 views

### Simple way to connect together two car alternators such that power flow can be bidirectional?

As I understand, it's not good to power a vehicle with two alternators, unless those alternators are protected in some way so that their voltage outputs don't go unstable (and die). I have an engine ...
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1 vote
187 views

### Why connect a 3-phase alternator's star-point to a rectifier bridge?

I noticed while troubleshooting a Denso alternator that the stator's star point was connected to the rectifier bridge. While probing with a multimeter, I think the schematic looks something like the ...
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216 views

### Adding a charging lamp indicator to an alternator not having a connection for it

I have this car alternator wired as follows: So it's connections are: B+ output for charging the battery, one brush to the regulator sense wire (exciter), and the other brush to ground. Is it ...
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495 views

### Will two alternators in parallel share the load all the time or will switch the load from one alternator to the other?

If two identical voltage sources are connected in parallel and supplying a load the load current will be the same since the voltage is the same, but each source will supply half the current demanded ...
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### How to connect a digital meter between alternator and batteries?

We are using a 24 V, 100 A external alternator in our vehicle to charge leisure batteries. We need to monitor the alternator’s voltages and current on a digital meter but the alternator is grounded ...
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133 views

### Crank an electric generator gasoline engine by using its alternator

Currently I have a gasoline generator (2 kW 230 Vac single phase), which has an electric starter. I'm searching for a potential replacement, but the brands I like doesn't have one around that power ...
• 11
1 vote
180 views

### Does car alternator speed increase during load dump?

I am trying to understand the mechanism of voltage surges during load dump in automobiles. As per this article - The load-dump event has two components. First is the pulse amplitude (VP), which ...
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232 views

### Voltage generated by individual coils goes down the larger the number of coils

I'm trying to make my own alternator & study the physics behind it. So I have a circle of magnets rotating over 4 coils, forming a square (90 degrees each). When I remove 3 coils from the square ...
3k views

### Does using a car’s electricity use up more fuel?

My understanding is that a car’s engine drives an alternator, which generates electricity to charge the car’s battery, and that all electrical power is then taken from the battery. If so, does this ...
127 views

### Solution of a differential equation of a RC filter (alternating voltage) and graph

I'm trying to solve the differential equation of a circuit on the capacitor for the first half-period (the capacitor is initially discharged): So far, I have this differential equation: RC_{1}\frac{...
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1k views

### I need to know what the resistance of the stator and rotor windings are

How do I calculate the resistance value of an alternator stator? 2.5 kW 50 Hz 220 V 8.3 A 12 V
126 views

### LTspice model single-phase motorcycle alternator

These days I'm dabbling in the design of a regulator for a 50cc motorbike, and I have a doubt how I can simulate the alternator on LTspice. Doing various tests on LTspice I arrived at a sinusoidal ...
292 views

### In AC circuits, angles and frequency are measured in radians rather than degrees. Why?

Why do we use radians instead of degrees when working with alternators and the like? The maximum induced EMF in an alternator will be a completely different value if one calculated ω in degrees per ...
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479 views

### Permanent magnet vs wound alternator

I have a buggy/go kart project, and am currently trying to decide on a battery charging solution. It is fully custom, so it is up to me to choose the device and build mounts, pulley ratio, etc. Many ...
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1 vote
67 views

### What are overhang conductors?

I am asking this in the context of synchronous generators. From the textbook "The Performance and Design of Alternating Current Machines", page 421, under the heading "3.Synchronous ...
637 views

### Why is this ideal diode bridge rectifier simulation in LTSpice not working as expected?

I'm trying to simulate a full wave bridge rectifier circuit with the capacitor filter. The alternating voltage supply is 30 V at 50 Hz. The peak value for the voltage across the load is 28.5 V. ...
42 views

### How do I safely power a triphase motor and an electric hoist with a triphase AC alternator?

The alternator has 12 kW, 21.7 amps and 400 V. For the motor we have 3/3.3 kW, 11.7/6.8 amps then 220/380 V and 250/440 V. The electric hoist we have 900 W and 220-240 V.
• 1
162 views

### On a 12 V car alternator with possible failure of the rectifier diode causing drainage, could an electronic component be added in-line near battery?

On a 12 V car alternator with possible failure of the rectifier diode/s causing drainage, could an electronic component be added in-line near the battery? Such as a voltage regulator or diodes in line ...
1 vote
1k views

### Charging a LiFePO4 battery from an alternator

I have a power bank consisting of two LiFePO4 cells connected in parallel. They will used to power a range of 12 V electronics e.g. fans, fish finder, USB chargers, L.E.D lights and potentially a ...
637 views

### Voltage output of a engine alternator

If an alternator is rated at 100A/13.5V then that's 1350Watts. Assuming an external regulator and a external rectifier what's to stop that same alternator outputting 28A/48V. Everywhere I have read, ...
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5k views

### Understanding alternator wiring

The alternator on a 2018 mitsubishi outlander along with many other vehicles has a 4 wire connector going to it. They are labelled as follows: G-Ground S-Sense L-Lamp FR-Field Ground - is self ...
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1 vote
966 views

### what force is required to rotate a dynamo or alternator

I am working on an initiative for a new product. The product generates a rotational output force from: Input force of 14.73 NM Input speed 120 rpm Gear ratios from 0.5 - 2 The out rotation is ...
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124 views

### Reactive power fluctuation

We have 6 Caterpillar gas generators 3520c. One of them when synches with the grid. Its kVAR fluctuates over wide range and the aux voltage too and the excitation volt and current. We checked AVR and ...
370 views

### What happens if you connect an AC generator to an AC motor? [closed]

An AC generator (or alternator) converts mechanical energy into electrical energy. An AC motor does the reverse. What would happen if we connect the two in such a way that the output rotational ...
572 views

### Actual Line-to-Line voltage from per unit value

In this question, I am able to find the per unit phase voltages using the symmetrical components. Taking the base MVA and base voltage to be the same as that of the alternator, \\$ (I_a)_1 = \frac{E_a}{...
3k views

### Can an alternator recharge a battery in an EV

Can you recharge a EV's electric battery with an alternator hooked up to the axle of the EV? This question came from a conversation with my Grandpa, and I was looking for an explanation for him of why ...
1 vote
1k views

### Looking for solution to energize a relay ONLY when the alternator is running

I added a DC-DC converter in my truck so that I can charge the Lithium batteries in my RV. To turn on the converter, I am using a relay that ties to upfitter switches in my Ford F350 truck. This all ...
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144 views

### 24 V alternator to 24 V motor

I plan to run a 400 RPM, 400 W, 24 V AC alternator through a bridge rectifier, then through a 25 V smoothing capacitor, and then drive a 24 V, low-RPM DC motor. I would like advice on specifics. ...
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1 vote
93 views

### What is the net current through this LR circuit

Here is the problem which I was asked to do. I started by the method of phasors considering first the upper branch of the circuit Drawing phasors as follows : Then for the lower circuit i drew the ...
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1k views

### Does Alternator Self-Excitation Require Rectification?

I am learning about self-excitation in alternators. My understanding is that there is residual magnetism in the rotor. As it spins, this generates a current in a stator which is then fed to the (...
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759 views

### Alternator's saturation in load and no-load conditions

When a ferromagnetic material is exposed to a magnetic field in which it moves, some voltage is induced in the material. If you increase the magnetic field, the voltage is increased up to a point, and ...
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628 views

### Alternator motor on 3 phase power

Hi was wondering would a alternator work as a motor if supplied dc power to the rotor and 3 phase ac to the stator. Have seen a lot of posts and videos turning it into a bldc motor but none on turning ...
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1 vote
154 views

### Design principles that prevent overcharging of batteries in older vehicles without undercharging

This question is regarding older (10 to 30 years old) cars which did not have a smart solid-state or electronic charger built in. Basically, lead-acid batteries in such cars were (and in cheaper cars, ...
164 views

### Using bridge rectifier on failing alternator output?

I have a bridge rectifier (because it was what was readily available as an integrated part) rated at 150A which I'm using to protect against intermittent reverse current (battery draining) in an ...
1 vote
1k views

### Car battery > inverter > battery Maintainer > Same car battery = jumper cables in the trash?

I'm wondering if I have my car battery hooked up to a power inverter hooked up to a battery maintainer hooked up to the same car battery will it prevent me from needing to jumper cable my car? I ...
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1 vote
988 views

### Designing an automotive alternator's voltage regulator - how to avoid magnetic saturation in the rotor?

NB: See final edit. The question is based on a false premise Friends are making a test-bench for automotive ("Lundell") type alternators. They were supplied with an example alternator plus a ...
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48 views

### Three phase power supply for test purposes

I work in the electrical industry and deal with mainly three phase power. I'm trying to broaden my knowledge of scopes and power quality and the only time I really have to do this is at work and that ...
1 vote
170 views

### Can steel nails be substituted for the silicon steel laminate in a motor/generator/alternator?

This is as diagram of a generator/alternator in which steel nails are used in place of silicon steel laminates:
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### Honda CBX 1979 Regulator/Rectifier - Lipo (lifepo4) battery

I exchanged the OEM battery (PB) of the CBX 1000 motorcycle with a Lifepo4 12V battery. It is smaller, lighter and has a much better CCA. However, the connector (wires at the bottom side of photo) ...
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