Fuse size for starter solenoid?

[atlarge54]

I'm running a wire from the battery to the starter solenoid on a MF 230 (3 cyl Perkins diesel). The plan is to use an inline fuse holder from the battery to the starter button then to the safety inerlock then to the solenoid. According to an internet search a typical 12v starter solenoid draws around 8-10 amps. Also anyone familiar with the safety interlock on the MF 230 does it operate from the clutch, hi-lo range neutral or trans neutral?

 

[Jim.ME]

I'm running a wire from the battery to the starter solenoid on a MF 230 (3 cyl Perkins diesel). The plan is to use an inline fuse holder from the battery to the starter button then to the safety inerlock then to the solenoid. According to an internet search a typical 12v starter solenoid draws around 8-10 amps. Also anyone familiar with the safety interlock on the MF 230 does it operate from the clutch, hi-lo range neutral or trans neutral?

I believe if you had the wiring diagram for that tractor it would show you a 20-amp fuse in the wire between the ammeter and the start switch. The starter switch and the oil pressure switch are both fed by that fuse. It would be one of the two fuse holders in the dash, the other one would be for the lights. The 230 has a neutral start switch controlled by the High/Low range shifter being in neutral for starting.

Massey Ferguson put most wiring diagrams in the Operator's Manuals during that vintage. I suggest you get a copy of the 230 Operator's Manual.

 

[John T]

The purpose of the fuse is TO LIMIT CURRENT AND PROTECT THE WIRE from overcurrent. IE if your wire is rated for 20 Amps, you would protect it with no bigger than a 20 Amp fuse. And likewise, ifffffffffffff you use a 20 amp fuse, the wire should have an ampacity of at least 20 Amps. If the load is the 10 Amps you say, I would use 20 Amp rated wire even if 16 amp wire would suffice, and protect it with a 20 Amp fuse. Its an electrical question so others might add to this.

John T

 

[used red MN]

It sounds like you are modifying or trying to add to the original wiring of the tractor starting circuit yet still utilize the “safety interlock” what is the reason for this? Repairing the original wiring if there is a problem with the start circuit is the best plan.

 

[Jaden]

For inductive loads, such as a solenoid, I prefer a Slow Blow fuse to avoid nuisance trips.

 

[Jim.ME]

I described the wiring diagrams shown in the MF Operator's Manuals I have for the MF245 and MF255 (sisters to the MF230). I only said "I believe" because I don't have the actual MF Operators manual for a MF230. It has a 20-amp common glass fuse in the OEM wiring. Basically, the only difference from atlarge54's plan is MF takes the switch power from the ammeter. And the wires for the start circuit control are all called out as 14 gauge. I have had no trouble with nuisance trips using the proper sized glass fuses on my Masseys.

 

[atlarge54]

I believe if you had the wiring diagram for that tractor it would show you a 20-amp fuse in the wire between the ammeter and the start switch. The starter switch and the oil pressure switch are both fed by that fuse. It would be one of the two fuse holders in the dash, the other one would be for the lights. The 230 has a neutral start switch controlled by the High/Low range shifter being in neutral for starting.

Massey Ferguson put most wiring diagrams in the Operator's Manuals during that vintage. I suggest you get a copy of the 230 Operator's Manual.

My apologies for not having or purchasing a manual. I did an online search and the results were rather sketchy at best.

I've had this tractor under a carport for ten years and just plan to get rid of it. Pretty surprised it starts and runs quite well. It seemed like without too much effort fixing the starter button would be quite an improvement to just touching a wire to the battery terminal.

Thanks to all who replied.

 

[Jim.ME]

My apologies for not having or purchasing a manual. I did an online search and the results were rather sketchy at best.

I've had this tractor under a carport for ten years and just plan to get rid of it. Pretty surprised it starts and runs quite well. It seemed like without too much effort fixing the starter button would be quite an improvement to just touching a wire to the battery terminal.

Thanks to all who replied.

The wiring info I posted follows the drawings in the manuals. Having the start system (including the neutral start safety) working correctly before you sell it, is a good plan. Good luck.

 

[John T]

My apologies for not having or purchasing a manual. I did an online search and the results were rather sketchy at best.

I've had this tractor under a carport for ten years and just plan to get rid of it. Pretty surprised it starts and runs quite well. It seemed like without too much effort fixing the starter button would be quite an improvement to just touching a wire to the battery terminal.

Thanks to all who replied.

Thanks for the update

John T

 

[Geo-TH,In]

I'm running a wire from the battery to the starter solenoid on a MF 230 (3 cyl Perkins diesel). The plan is to use an inline fuse holder from the battery to the starter button then to the safety inerlock then to the solenoid. According to an internet search a typical 12v starter solenoid draws around 8-10 amps. Also anyone familiar with the safety interlock on the MF 230 does it operate from the clutch, hi-lo range neutral or trans neutral?

Fuses are cheap. If you can't measure the current I would recommend you use the fuse for the wire size.
Good chance your wire will be 14g, 15 amps.
I rewired my Jubilee using 14 wire.
No rule against using a smaller fuse. Fuses are cheap.

I worked on a lawn mower that was wired with 14g and it came from the factory with a 20 amp fuse. I guess JohnT didn't fork for Husqvarna or they would have used a smaller fuse.
The mower was blowing the 20 amp fuse. Come to find out, the power wire on the electric clutch, PTO clutch, was shorted to ground.
This redneck just cut the plug and made the power wire the ground wire and the ground wire became the power wire.
Then I fused the PTO with a 10a fuse..
All is good.

I rewired my Jubilee using 14 wire. Each circuit has a different fuse. Lightning, ignition, alternator, and gas solenoid.
Using fuses for different circuits makes it very easy to tell what circuit has a short.

 

[Geo-TH,In]

For inductive loads, such as a solenoid, I prefer a Slow Blow fuse to avoid nuisance trips.

I never heard of calling a solenoid an inductive load when using DC voltage.
Unlike capacitors, the current in a solenoid takes a short time to become full current, no surge current.
Capacitors are the opposite.
Inductive reactance is calculated my multiplying frequency times inductance times inductance times 2 pi.
DC V has no frequency, so the solenoid had no inductance.
I may be wrong. I don't agree. No need for a slow blow.
What does JohnT say?

I bought 100 20 amp fuses from Amazon for about $5.
I don't think the flat fuses used today in cars and trucks are slow blow.

 

[RJKeith]

A few thoughts on fuse size. First, many claim that the fuse is sized to protect the wire. The fuse is sized to protect both the wire AND the device, such as the solenoid

Second, many talk about current rating for different size wires. The NEC table those values come from is for 3 current carrying wires in conduit and based on insulation type. Wires on a tractor are typically individual in free air, so they can carry a higher current. However, values for #14, #12, and #10 wire are based on the heating of the connection due to the smaller connecting area on smaller wire. A nit picking but important detail.

Third. the wire sizing is also for long term use of the load, such as a running fan motor. But while the wire must be sized for 1.25% of the fan motor full load amps, the inrush current on starting the motor can be six times the full load amps. But the wire is fine because of the short duration of this current. The math is Current Squared x Time.

Fourth, the solenoid, as well as the starter, isn't engaged but for a few seconds. Nothing on those two devices is sized for continuous use. Crank an engine for several minutes and the starter will start to smoke. So the solenoid's real protection against heating isn't the fuse sizing, it is the limited time of use of the solenoid. The recommendation above for a delayed fuse is a good idea. If the fuse size is too big, you will still be protected from a short circuit, but is the fuse size is a little too small, your tractor should start before the fuse blows.

Try to find the right size, but the time delay will forgive a small mistake on fuse size. A longwinded answer, but hopefully it helps.

 

[wore out]

I'm running a wire from the battery to the starter solenoid on a MF 230 (3 cyl Perkins diesel). The plan is to use an inline fuse holder from the battery to the starter button then to the safety inerlock then to the solenoid. According to an internet search a typical 12v starter solenoid draws around 8-10 amps. Also anyone familiar with the safety interlock on the MF 230 does it operate from the clutch, hi-lo range neutral or trans neutral?

An easy alternative to protect a circuit that is unlikely to fail/short but is there "just in case" is to use a "fusible link".

http://www.madelectrical.com/catalog/fusible-link.shtml

 

[John T]

Fuses are cheap. If you can't measure the current I would recommend you use the fuse for the wire size.
Good chance your wire will be 14g, 15 amps.
I rewired my Jubilee using 14 wire.
No rule against using a smaller fuse. Fuses are cheap.

I worked on a lawn mower that was wired with 14g and it came from the factory with a 20 amp fuse. I guess JohnT didn't fork for Husqvarna or they would have used a smaller fuse.
The mower was blowing the 20 amp fuse. Come to find out, the power wire on the electric clutch, PTO clutch, was shorted to ground.
This redneck just cut the plug and made the power wire the ground wire and the ground wire became the power wire.
Then I fused the PTO with a 10a fuse..
All is good.

I rewired my Jubilee using 14 wire. Each circuit has a different fuse. Lightning, ignition, alternator, and gas solenoid.
Using fuses for different circuits makes it very easy to tell what circuit has a short.

Yo George, when I was practicing electrical power distribution For the record had I worked for Husky or anyone else the way I was taught by NEC instructors and in accordance with NEC and other industry standards was to 1 compute the maximum continuous current 2 size the wire to have an ampacity of at least 125% of the mcc 3 select overcurrent protection to match the wires ampacity. If the mcc was say 10 amps I’d select wire rated at least 13 amps and protect accordingly however if the size were not standard I upgraded to the next size. After all that voltage drop was calculated and if necessary wire size was increased in which case if the wire was upgraded from for example 15 to 20 amp rated a 20 amp fuse would be used. Without the mcc and line voltage drop the wire and fuse can’t be calculated but often if the exact full mcc or voltage drop isn’t known the designer may upgrade 15 amp wire to 20 and fuse accordingly. Of course we have no way of knowing what husky did or why 15 or 20 amp wire may have been used.
Hope this helps you nice chatting neighbor good luck in your new car purchase and again if I was looking at caddy’s I’d go with a v6 yayyyy

Best wishes neighbor

John T

 

[Jim.ME]

Unless someone has removed it the MF230 has a fuse holder for a 20-amp fuse in the dash that that the starter button/switch circuit power is supplied by. It is by the OEM drawings; it works on my Masseys; I think it will on his. He wants to sell the tractor, the nearer original the better in my thoughts.

 

[Geo-TH,In]

Yo George, when I was practicing electrical power distribution For the record had I worked for Husky or anyone else the way I was taught by NEC instructors and in accordance with NEC and other industry standards was to 1 compute the maximum continuous current 2 size the wire to have an ampacity of at least 125% of the mcc 3 select overcurrent protection to match the wires ampacity. If the mcc was say 10 amps I’d select wire rated at least 13 amps and protect accordingly however if the size were not standard I upgraded to the next size. After all that voltage drop was calculated and if necessary wire size was increased in which case if the wire was upgraded from for example 15 to 20 amp rated a 20 amp fuse would be used. Without the mcc and line voltage drop the wire and fuse can’t be calculated but often if the exact full mcc or voltage drop isn’t known the designer may upgrade 15 amp wire to 20 and fuse accordingly. Of course we have no way of knowing what husky did or why 15 or 20 amp wire may have been used.
Hope this helps you nice chatting neighbor good luck in your new car purchase and again if I was looking at caddy’s I’d go with a v6 yayyyy

Best wishes neighbor

John T

JohnT
A lot of words that didn't explain why husky used a 20 amp fuse and 14g wire.
Forget the test of the line drop, 125% ruel and length of the wire, irrelevant here..
Fuses are to protect the wire.

Is a coil considered an inductive load on 12v DC?
Is the current in the coil minimum or max when first connected to 12 v DC?

 

[used red MN]

The wiring info I posted follows the drawings in the manuals. Having the start system (including the neutral start safety) working correctly before you sell it, is a good plan. Good luck.

Atlarge, maybe to be more direct Jim.ME is suggesting you try to find the fuse in the original wiring and check it to see if that is your problem. It looks like the fuse holder is actually right in the dash. In the link go to section 78, the fuse holder is #17. AGCO MF230 parts

 

[John T]

JohnT
A lot of words that didn't explain why husky used a 20 amp fuse and 14g wire.
Forget the test of the line drop, 125% ruel and length of the wire, irrelevant here..
Fuses are to protect the wire.

Is a coil considered an inductive load on 12v DC?
Is the current in the coil minimum or max when first connected to 12 v DC?

Good morning George, to your statement A lot of words that didn't explain why husky used a 20 amp fuse and 14g wire.

Short Answer FYI a Conductor in FREE AIR has a much higher Ampacity versus if enclosed, see below the wire in question may be rated for 20 Amps !!!!!!!!!!!!

George THERE IS NO WAY SITTING HERE ABSENT ANY DATA, ABSENT EXACT CURRENT, ABSENT ANY VOLTAGE DROP OR WIRE RATINGS OR THE TYPE, CLASS AND TEMPERATURE RATING OF THE INSULATION, neither myself nor anyone (other than Husky) can tell you whyyyyyyyyyyyyyyyyy Husky used a 20 Amp fuse and 14 Gauge wire !!!!!!!!!!!!!!!!!!!! You will have to ask them........

HOWEVER FYI I can explain the engineering to try my best to help, thats ALL I can do sorry, you have to ask Husky.

HOWEVER I can tell you based on Insulation, based on its type, class and temperature rating, based on the wire and iffffffffffffffff its in free air or enclosed in a raceway or jacketing of what type (metallic or non metallic) and its environment THE WIRE USED MAY WELL HAVE AN AMPACITY OF 20 AMPS !! You nor I sitting here don't know ifffffffffffffffff the wire used, based on its insulation and if in free air, didnt have an ampacity of 20 Amps !!!!!!!!! Maybe yes ?????????

You see George, they may (or may not) have used a 20 Amp Overcurrent Protection Device to protect wire having an ampacity of 20 Amps !!!!!!!!!

YES you are correct when you state the Overcurrent Protection Device (fuse in this case) is to protect the wire

YES you are correct, a coil is an inductor type of device.

You ask a great question Is the current in the coil minimum or max when first connected to 12 v DC?

This may be over your head its EE 101, but here goes: At time T = 0+ an Inductor, which opposes sudden current change, is initially highly resistive (impedance) so initial current is low HOWEVER once the shock and attempt at a sudden current change decreases, its less resistive so CURRENT WILL THEN INCREASE IE to answer your question, CURRENT IS BRIEFLY MINIMUM when first connected

There ya go good neighbor, I hope this helps but don't feel bad if you don't get it as its impossible to describe here in a few sentences what may take books or an entire course to understand BUT HEY I TRY MY BEST TO HELP YOU and am glad to do so !!!!!!!!

Take care George, keep curious keep asking questions as that's the only way to learn

Best wishes neighbor

John T

 

[used red MN]

Good morning George, to your statement A lot of words that didn't explain why husky used a 20 amp fuse and 14g wire.

George THERE IS NO WAY SITTING HERE ABSENT ANY DATA, ABSENT EXACT CURRENT, ABSENT ANY VOLTAGE DROP OR WIRE RATINGS OR THE TYPE, CLASS AND TEMPERATURE RATING OF THE INSULATION, neither myself nor anyone (other than Husky) can tell you whyyyyyyyyyyyyyyyyy Husky used a 20 Amp fuse and 14 Gauge wire !!!!!!!!!!!!!!!!!!!! You will have to ask them........

HOWEVER FYI I can explain the engineering to try my best to help, thats ALL I can do sorry, you have to ask Husky.

HOWEVER I can tell you based on Insulation, based on its type, class and temperature rating, based on the wire and iffffffffffffffff its in free air or enclosed in a raceway or jacketing of what type (metallic or non metallic) and its environment THE WIRE USED MAY WELL HAVE AN AMPACITY OF 20 AMPS !! You nor I sitting here don't know ifffffffffffffffff the wire used, based on its insulation and if in free air, didnt have an ampacity of 20 Amps !!!!!!!!! Maybe yes ?????????

You see George, they may (or may not) have used a 20 Amp Overcurrent Protection Device to protect wire having an ampacity of 20 Amps !!!!!!!!!

YES you are correct when you state the Overcurrent Protection Device (fuse in this case) is to protect the wire

YES you are correct, a coil is an inductor type of device.

You ask a great question Is the current in the coil minimum or max when first connected to 12 v DC?

This may be over your head its EE 101, but here goes: At time T = 0+ an Inductor, which opposes sudden current change, is initially highly resistive (impedance) so initial current is low HOWEVER once the shock and attempt at a sudden current change decreases, its less resistive so CURRENT WILL THEN INCREASE IE to answer your question, CURRENT IS BRIEFLY MINIMUM when first connected

There ya go good neighbor, I hope this helps but don't feel bad if you don't get it as its impossible to describe here in a few sentences what may take books or an entire course to understand BUT HEY I TRY MY BEST TO HELP YOU and am glad to do so !!!!!!!!

Take care George, keep curious keep asking questions as that's the only way to learn

Best wishes neighbor

John T

In my opinion if you guys want to squabble about an individuals willingness or lack there of to consent to your urging then you should move your conversation to the PM feature.

 

[John T]

A few thoughts on fuse size. First, many claim that the fuse is sized to protect the wire. The fuse is sized to protect both the wire AND the device, such as the solenoid

Second, many talk about current rating for different size wires. The NEC table those values come from is for 3 current carrying wires in conduit and based on insulation type. Wires on a tractor are typically individual in free air, so they can carry a higher current. However, values for #14, #12, and #10 wire are based on the heating of the connection due to the smaller connecting area on smaller wire. A nit picking but important detail.

Third. the wire sizing is also for long term use of the load, such as a running fan motor. But while the wire must be sized for 1.25% of the fan motor full load amps, the inrush current on starting the motor can be six times the full load amps. But the wire is fine because of the short duration of this current. The math is Current Squared x Time.

Fourth, the solenoid, as well as the starter, isn't engaged but for a few seconds. Nothing on those two devices is sized for continuous use. Crank an engine for several minutes and the starter will start to smoke. So the solenoid's real protection against heating isn't the fuse sizing, it is the limited time of use of the solenoid. The recommendation above for a delayed fuse is a good idea. If the fuse size is too big, you will still be protected from a short circuit, but is the fuse size is a little too small, your tractor should start before the fuse blows.

Try to find the right size, but the time delay will forgive a small mistake on fuse size. A longwinded answer, but hopefully it helps.

Great info RJ thanks for your inputs, love this sparky chat !!!!!!!! While its been a longggggggggg time and codes may well change, during the time and in the jurisdiction where I last practiced at least (NEC had been adopted) the overcurrent protection device was used to protect the wire. HOWEVER in the case of motor loads if the motor was so equipped THE THERMAL OVERLOAD WAS WHAT PROTECTED THE MOTOR. IE the fuse protected the wire while the thermal overload protected the motor load. BUT THATS NOT THE END LOL For motors we may have had to use a Dual Element Time Delay Fuse to allow the motor to start due to the higher initial inrush current and today types of circuit breakers may be used (HACR is that right???)

EXACTLY AND SO TRUE (though some non sparkies, non electricians or non engineers may not have experience) a wires Ampacity depends on the conductor material and gauge,,,,,,,,,the type class and temperature rating of the insulation,,,,,,,,,,,,,the environment,,,,,,,,,,,,,,,if the conductor is in free air (MUCH higher Ampacity) or if in raceway or jacketed etc etc etc FOR EXAMPLE AS I DESCRIBED TO OUR FRIEND GEORGE ABOVE 14 Gauge wire may possibly have an Ampacity of 20 Amps !!!!!!!! I cant say from here way too many unknowns

I enjoyed and appreciate your post even if it may bore others lol I think it may well have helped ....

Take care best wishes its a pleasure sparky chatting with you........

John T Longgggggggggg retired and rusty EE so NO warranty, dont take my word for it, where fire and life safety are concerned CONSULT PROFESSIONALS AND THE NEC ..........