start a 12VDC 150 Amps electric motor

I have a diesel engine and that has a starter electric motor rated 12 VDC 150 Amps.

I am trying to make a project that allows me to start this engine using arduino.

Can I use http://www.dx.com/p/ssr-25da-25a-solid-state-relay-white-134494#.Vym1obNX40M relay to start my motor ? The relay in the above link is for AC load but I need a relay for DC load.

If no .. . Any suggestions on how to make this work.

First you need to establish if the starter motor has a solenoid built into it so that you are only controlling solenoid current or are you controlling actual motor current.

If the former and you want to use an SSR, then something like this might work
http://www.ebay.com/itm/SSR-40A-DD-DC-DC-5V-12V-32V-Solid-State-Relay-for-Temperature-Controller-Arduino-/361344740825
It is a DC output relay.

If, however you are having to control actual motor current then you will need something like one of these

and an SSR to interface it to your arduino

Your vehicle already has the device you need within it. Components in your vehicle currently control that device. One of those components is the ignition switch. Seems that interfacing to the ignition switch would make sense. ALSO attempting to engage a starter without considering other factors (e.g. is the vehicle in Park, Neutral? Is the ignition on?) may be a very bad idea.

  • Scotty

No one sad it was a vehicle. If it is then here is a classic case of asking for assistance without fully defining the problem.

manmohanbishnoi: I have a diesel engine and that has a starter electric motor rated 12 VDC 150 Amps.

I am trying to make a project that allows me to start this engine using arduino.

Can I use http://www.dx.com/p/ssr-25da-25a-solid-state-relay-white-134494#.Vym1obNX40M relay to start my motor ? The relay in the above link is for AC load but I need a relay for DC load.

If no .. . Any suggestions on how to make this work.

Is 150A the rating of the solenoid then? You will be driving the solenoid, not the motor of source.

AC relays cannot handle high current DC safely, DC arcs don't quench.

jackrae: If, however you are having to control actual motor current then you will need something like one of these http://www.ebay.com/itm/New-Solenoid-12V-15-450-SAZ-4201DX-Starter-Relay-7-1035-/270998463143 and an SSR to interface it to your arduino

150A is more than 100A. Recipe for disaster. I'd expect starter motors for diesel vehicles to be well capable of 400A peak anyway.

scottyjr: Your vehicle already has the device you need within it. Components in your vehicle currently control that device. One of those components is the ignition switch. Seems that interfacing to the ignition switch would make sense. ALSO attempting to engage a starter without considering other factors (e.g. is the vehicle in Park, Neutral? Is the ignition on?) may be a very bad idea.

  • Scotty

No it is not a vehicle. It is a simple diesel engine generator which i am trying to start using arduino. I will use android app to send a signal over wifi to start the generator in case ups battery are low on charge.

MarkT: Is 150A the rating of the solenoid then? You will be driving the solenoid, not the motor of source.

AC relays cannot handle high current DC safely, DC arcs don't quench.

I checked the generator's electric self connections and seems like the battery connects to the solenoid. But I am not sure that 150 Amps is rating for solenoid or motor.

I tried to check manufacturers website for details about the electric self but seems their website is outdated and product info is not available.

I was thinking of going with electromagnetic induction relay . . . .that can handle such large currents.

Oops I didn't look at the solenoid rating :disappointed_relieved: but i did say "...something like...." 8)

Does the engine have a key start If so then it'll probably have a 3 position switch Off - Run - Start On the assumption that it has such then you simply need a couple of relays driven from your arduino One to provide the Run function which will remain energised when the engine is required to run and a second one to provide the start function which will only be energised whilst the engine is being cranked.

One of the problems you will come up against is determining when the engine has actually started. You could achieve this by monitoring the generator output but some types are a bit slow at exciting once the engine is running. Alternatively you could monitor exhaust temperature and once the engine fires there will be a rapid increase in exhaust. Although the running exhaust may be several hundred degrees, setting a sense threshold of somewhat less than 100C might be sufficient to determine an "engine-running" status

You only need enough current capability to actuate the existing starter solenoid. For typical engine solenoids that will be 3A or less, but if you want to know for certain you could measure the resistance of the solenoid coil. Give us more details on the generator and a picture of the solenoid if you need additional explanation.

Simplest and most trouble-free way to actuate that solenoid would be with a relay module.

Chagrin: You only need enough current capability to actuate the existing starter solenoid. For typical engine solenoids that will be 3A or less

Ha! I doubt it, these are high power contactors that have to generate large forces, 10 to 20A is much more likely. The solenoid both pushes 300A contacts together and pushs the drive pinion along the motor shaft, a large mechanical load.

There may be a solenoid relay to boost the ignition switch to drive the solenoid, in that case the relay itself might only need a few amps, but the solenoid is a large high power electromagnet and contactor assembly.

Before you get too far along with this project, does your engine require heating of glow plugs, and/or compression release in order to start?

Exactly what steps do you perform now to start the engine?

Paul

MarkT:
Ha! I doubt it, these are high power contactors that have to generate large forces, 10 to 20A is much more likely. The solenoid both pushes 300A contacts together and pushs the drive pinion along the motor shaft, a large mechanical load.

The solenoid of the type I’m thinking of (Ford SW3), which is still extremely common for mowers or generators, is 4ohms across the coil terminals (i.e. 3A). These are rated 150A / intermittent duty.

Paul_KD7HB: Before you get too far along with this project, does your engine require heating of glow plugs, and/or compression release in order to start?

Exactly what steps do you perform now to start the engine?

Paul

It is a pretty simple diesel generator set with these specifications:

  • Engine : 12 HP
  • Fuel : Diesel
  • Output : 7.5 KVA
  • RPM : 1500

The generator engine can be started by simply rotating the key toward right and hold for 1-2 seconds and then the generators starts. Also the ignition key is automatically rotated back to it's original position as soon as you release it.

Here are few attached images.

|500x281

|500x229

|500x374

|500x384

To stop the generator one has to push/pull the governor towards right in the above image. I'll place a servo motor here to control the engine RPM and to stop generator in case grid power is restored.

|394x500

jackrae: Does the engine have a key start If so then it'll probably have a 3 position switch Off - Run - Start

One of the problems you will come up against is determining when the engine has actually started. You could achieve this by monitoring the generator output but some types are a bit slow at exciting once the engine is running.

It is a simple ignition key switch that has Off - On positions. To stop the generator one has to move governor towards right (see image in above reply)

Engine has started can be determined by sensing output voltage or shaft RPM . . .we'll let's try to start this engine first :)

Please please when you first post explain exactly what you have - it took a long while before any mention of a generator - so everyone assumed a diesel engine for a vehicle.

In general identify every piece of hardware fully - part number or datasheet, not a vague textual description.

This is all mentioned in the guides to posting here.

Your pictures explain much more that you have written. The Diesel engine is one probably made in India. They were imported into the USA in the 1990's for use with off-grid generators and water pumps. Then disappeared.

The engine is very low compression and can be hand-cranked to start. One of the pictures shows the front shaft crank has been used quite often.

That said, the starter motor does not work very hard to start the motor. Don't monkey with the governor. To shut the engine down, put a normally open solenoid valve in the fuel line. There is no pressure in the line, only gravity feed. Close the solenoid for a time, to be determined, until the engine stops.

The engine will not come up to the rated 1500 rpm very quickly, so monitoring the generator voltage to determine how long to engage the starter is not a good idea. You need something else to tell you the engine is running. Perhaps a pressure sensor in the exhaust. Or just a piezo fastened to the exhause to detect the first engine firing.

Looks like a good project for your Arduino. Not complicated at all!

Paul

While working out on the treadmill, I meditated on your project. I think, now, the governor is how you shut the engine down, now, so that would be better than shutting the fuel off and perhaps having to bleed the injector.

The first order of business hardware and programming wise is to be able to determine if the engine is running or not running. Everything your program will be doing will require it to know the answer.

So, are you able to fabricate a microswitch with an air flap to monitor the engine exhaust? With gravity holding the flap down, the switch will tell your program the engine is not running. When the exhaust pushed the flap away, the switch will tell your program the engine is running.

When that is working, move the code into a function that can be called from many parts of your ultimate program.

Paul

MarkT: Please please when you first post explain exactly what you have - it took a long while before any mention of a generator - so everyone assumed a diesel engine for a vehicle.

In general identify every piece of hardware fully - part number or datasheet, not a vague textual description.

This is all mentioned in the guides to posting here.

My apologies for not clearly explaining the details of hardware. Won't happen again.

Paul_KD7HB: The first order of business hardware and programming wise is to be able to determine if the engine is running or not running. Everything your program will be doing will require it to know the answer.

I'll look for all possible solutions to determine that engine is running or not. Air flap switch, engine rpm monitoring, etc and use the best option fit for my needs.

manmohanbishnoi: My apologies for not clearly explaining the details of hardware. Won't happen again.

I'll look for all possible solutions to determine that engine is running or not. Air flap switch, engine rpm monitoring, etc and use the best option fit for my needs.

As this engine is used in many applications, your program should become very useful in irrigation systems, etc.

Paul