Questions tagged [alternator]

Electrical generators that produce alternate current.

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18 views

When changing rotor current in alternators, the pf and inductive part of the current changes but the resistive part does not. Why is this so?

Given a current for an alternator $ I = I_R - jI_X $ When the rotor current changes, the excitation changes so the magnitude of the generated voltage changes. The current changes, but only the ...
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Car alternator broken soldering joint

so it was very cold in my country last week and my car alternator died. I took it out and I found that one coil wire, which connects to rectifier is broken and there is no contact (I guess it could ...
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46 views

How is it that the induced EMF in an alternator is in quadrature with the main flux?

Looking at the simplified diagram of an alternator, the flux "linked" with the conductor is maximum at 90, 270 degrees, is also when induced EMF is maximum. So isn't the main flux in phase ...
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37 views

Counter torque in alternator supplying reactive power

When an alternator(assume zero armature resistance and iron loss) is supplying purely lagging/leading current, which means there is no work done by the current supplied, does that mean the counter ...
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52 views

How can you predict the power an electrical generator (alternator) produces?

We have to design an electrical alternator in a multiphysics software, but we can't seem to figure out how to deduce the power it will produce. We need to charge a capacitor to 1000 joules (at 2000V) ...
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85 views

Car Battery Voltage

Why is the voltage of a car battery rated for say 12V around 14V when the car is running? Is it because of the alternator?
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85 views

Regulating voltage from an alternator [closed]

I asked a question about voltage regulators but didn't get a proper answer, so here's a new one. So i have this motorcycle with an alternator. The alternator gives out about 3 volts at idle speed, but ...
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54 views

Determining number of poles on permanent magnet alternator

I was able to buy a cheap used permanent magnet alternator, however the seller was not able to tell me much about the specifications. I could determine that it has a built in voltage regulator, ...
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1answer
56 views

Which form between solar panel and wind turbines requires less cost in servicing?

I found that the average life of a solar panel is about 25 years and that of the the wind turbine is also somewhat close to 25 years. But the wind turbines require alternator in order to generate ...
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156 views

How can I calculate the internal resistance of an alternator?

I have a 12V, 90A alternator. I wanted to know how can I calculate its internal resistance. The specifications sheet I received from the manufacturer is a simple image, as shown below: I This ...
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69 views

Using rectifier + inverter to get 50Hz AC output

I am currently in the theoretical (until I am very sure that it is safe) situation that I have an alternator powered by a gasoline engine that provides 220V 1500W AC power with RPM dependent frequency....
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166 views

What determines the frequency of alternating current?

I am certain this question has been asked before but I search and cannot see anything just yet. I read most AC current is 60 cycles per second in the United States and some say 50 but that does not ...
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99 views

Old lead-acid battery inrush charging current

Can an old lead-acid battery have an usually high inrush charging current, such that the alternator belt squeals for the first 30-90 seconds after the engine is started? It is worse in hot weather. ...
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63 views

Is the calculation of weight to be suspended inorder to produce electricity from an alternator correct or not?

I bought a alternator with the following specs: power: 5 hp rpm: 1800 voltage: 220V The formula for finding the horsepower is: horsepower= (RPM X Torque)/5252 By substituting the value of horsepower ...
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203 views

Alternator output rating

Overview: I am currently working on a project that requires a 24v alternator, which is powered by a mower engine. This engine in particular runs around 3,000 RPM, and does not exceed 3,200 RPM (based ...
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2k views

Tantalum Capacitor Explodes When Engine Starts

I designed a circuit using a SMPS voltage regulator based on the tps65261rhbr triple synchronous buck converter. The circuit is rated for up to 18V. It is connected to a 12V lawnmower battery, which ...
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62 views

An AC generator can 'lock up' if its timing is off? [closed]

I believe I read elsewhere on Stack Exchange (Physics or Electrical Engineering) about how an alternating current generator can seize up if the frequency of the current does not match something else ...
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81 views

Modifying brushless alternator for external regulator

I'd like to modify a Delco Remy 38si or 40si brushless alternator for use with an external voltage regulator. For a brushed alternator, I'd just need to pull the field out external to the case. My ...
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36 views

Selecting the right PMDC motor and battery

I'm looking at generating electrical energy from a mechanical input being used to rotate the shaft of a Permanent magnet DC motor. However, i'm a bit stuck with selecting the right motor and battery ...
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192 views

Attempt to build DIY high current power supply from car alternator?

Recently I had posted about a thread related to a bench DIY high current transformer 12VDC supply that I'm trying to built. But due to some transformer and diode rectifier limitations that project may ...
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Determining synchronous impedance by Simulation of an Alternator Test using MATLAB/Simulink

I would like to know if there is a way to simulate an alternator using MATLAB/Simulink to obtain the synchronous impedance of any alternator by using Open-Circuit Test and Short-Circuit test. Is this ...
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3answers
702 views

How can excitation be used of an alternator to control the power factor?

Looking for ways the excitation of an alternator can control its power factor?
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111 views

How to wire a single wire alternator to a bridge rectifier?

I'm trying to make a 25cc weed eater generator (for fun) and I'm thinking of using an alternator to take the rotary output from the engine and turn it into electricity. I need a way to take the 12-14V ...
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151 views

reactive power in induction machine

Does an induction machine actually consume reactive power?
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384 views

To what extent are alternators “flexible” to variations in input speed and output voltage?

An automotive-style alternator works from 750 RPM to e.g. 7000 RPM, a range of nearly 10:1. In terms of output voltage, I know they target a fixed output voltage, but I believe it wouldn't be too ...
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48 views

Finding Impedances on a Network

Hey there the first part of the question (finding the new C value) is pretty easy. However I am stuck at the second part, it asks me to find the empadance values and etc. Can you help me with that?
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282 views

What will happen if the prime mover driving synchronous machine is accidentally disconnected?

What happens to a synchronous machine connected to an infinite grid, acting as a generator, when its prime mover fails i.e. when mechanical input at the shaft reduces to 0? I'm assuming that the ...
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45 views

Improving a permanent magnet alternator. Replacing magnets / reducing air gap

In the case of a 3 phase PMA radial flux type, used as a wind turbine, with magnets on the surface of the rotor, is it safe or even doable to stack another magnet with the same geometry on top of the ...
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72 views

Relating input torque on BLDC motor shaft with output current

I am trying to build a drone generator with a gasoline engine and a 14-pole,170KV, 2KW BLDC skateboard motor (this one). Before designing the system and running it, I wanted to clear out a fundamental ...
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96 views

Current delivered by the vehicle alternator

I have a vehicle alternator with following parameters: 14V, 140A. In parallel to this alternator is connected 14.4V vehicle lead acid battery. The alternator is used as a power source for a load which ...
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83 views

Control of battery charging

I have been developing a control software for charging and discharging battery in a dc grid. The system consists of: 01) Three phase alternator with three phase diode bridge rectifier at its output ...
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396 views

Excitation current calculation for alternator

I have an old brush alternator where field excitation happens in the stator. Unfortunately no information is given about the required field excitation current. The alternator is rated 3 Phase, 400V, ...
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41 views

Selecting an alternator/generator

I am designing anenergy regeneration system using a pulley attached to the wire rope of a track elevator using a 3:1 sprocket ratio I am getting around 670 RPM`s I am using two 6 volt lead acid ...
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119 views

How to transform an AC signal of wide voltage to pulses

I want to build a device that measures frequency of possibly different electrical alternators, not having much control of their parameters. For this I need to get digital pulses out of the AC signal ...
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262 views

What is the source of reactive power generated by the alternator?

We know an alternator or in general any source of energy does not generate energy but converts one type of energy into some other usable form. An electric generator produces both real and reactive ...
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91 views

Help me understand my campervan split charge relay

I am new to the world of electronics, but keen to learn. The below all relates to the 12 V circuit of my van. I have picked up a campervan which has a second "leisure" battery which powers items in ...
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210 views

Vehicle Alternator/Inverter system

I have a food van with a stock alternator on the engine, and a 3000w inverter setup. The inverter setup uses 2 Trojan leisure batteries. Somehow the inverter setup is also linked to the alternator (I’...
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321 views

Free Piston Stirling Engine Tuning Capacitor - Series Vs Parallel

Why is a tuning capacitor placed in series with a free piston stirling alternator rather than parallel with it? I am accustomed to seeing power factor correction capacitors placed in parallel in ...
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204 views

Alternator droop characteristics

Two synchronous generators operating in parallel supply a total load of 200 MW. The ratings of the machines 1 and 2 are 100 MW and 200 MW. Machines 1 and 2 have governor droop characteristic of 4% and ...
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Alternator field winding VS equivalent inductor

I have a question which I know is going to be more opinion biased than factual. I know this isn't the purpose of the forum, but I would really appreciate some extra opinions so I'm going to ask it ...
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224 views

How to remove flickering on car-powered LEDs?

I am powering an array of LED lights via the car alternator (the LEDs are connected to the car battery leads, but only run when the engine is on). The problem with this setup is that the natural ...
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102 views

Open-circuit alternator

Is it dangerous to run a permanent magnet alternator open-circuited? No current can flow so is all the power dissipated as heat? Is there even power generated in the inductive coils?
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712 views

Can I use a MPPT Solar Controller to charge my auxillary 12V AGM Battery from the car battery/alternator?

I have a RedArc solenoid and a Victron 75/15 Smart Solar Controller. Can I use the combination of these two units to charge an 12V AGM Deep Cycle auxiliary battery from the car battery/alternator ...
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121 views

Automotive alternator

I have been working on a project where so called Lundell alternator plays a crucial role. I haven't got any experience with this device sofar so I have decided to study some literature regarding this ...
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107 views

Van with Solar power but no auxillary battery and only on sunny days. Do I need switches and isolators?

I have a 2018 Ram Promaster city cargo van with OEM 12v 70AH 120RC Sealed Led acid battery and a 160a alternator. Sitting on top of the battery I have a 1200 Watt pure sine 110v inverter connected ...
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261 views

One Way Current Restrictor

Will the below circuit act as a one-way current restrictor to allow 100A to flow out of the battery, but limit charging current to 10A into the battery from the alternator?
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Alternator current when charging flat battery

I've found some voltage-current-rpm graphs for car alternators and did not quite understand one thing. Basically, my alternator is rated at 75A (small car), which it should output above 2000 RPM or so....
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317 views

Impedance of individual component in complex AC circuit

In a AC circuit with just a capacitor or inductor, reactance is the impedance of the component, and in a non-complex RLC circuit you can just find the total impedance with vector addition (Ztot = sqrt(...
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Charge AGM battery from car alternator

What is the most efficient way of charging an AGM battery using a car alternator? I have a 12V plug connected to alligator clips which can be used in the 12V sockets inside the vehicle. Is this the ...
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89 views

4 channel digital scope

I wish to view 3 phase waveforms from an alternator (DUT) through isolation transformers via a digital oscilloscope. A 4 channel oscilloscope is obviously ideal for this as I can view the waveforms as ...