Mosfet swap

[whatever]

I'm working on a Shopride mobility scooter, 24v brushed motor and very nice old controller ( 1997 approx)made in england ( Penny and Giles Drive Technologies Christchurch, Dorset UK).
While checking the controller board for damage I noitced a small burn mark on the back of a small mosfet, the highly heated area on the metal backing of the mosfet was between the gate and drain area, but after taking out the fet and testing it , it appeared to still be working. When back in the scooter it appears sometimes it works, sometimes it doesn't. The mosfet is LU014, data sheet says its N-chanel 60v and 30amp cont., its small package t0-251, much smaller than the typical ebike controller fets.
These mobility scooters have an electric brake which is always on ( when no power), and releases when the throttle is applied, this mosfet seems to supply this ebrake via a relay.
So you hit the throttle you hear a click of the relay and the brake releases and the controller then acts as typical brushed ebike controller to power the motor.
This mosfet not related to powering the motor at all.
My question is:
could I replace this mosfet with another N-chanel mosfet which has same voltage rating (60v) and similar amp rating? Do I have to worry about what voltage is going to the gate during on state? Does that vary between fets? I have plenty of different fets on hand but dont want to accidentally fry anything by puting a different fet in there. I dont think there is much amps goes through this fet, the electric brake only draws about 1/2amp ( not sure if the relay is also powered by this fet, relay wouldn't draw much current either). The electric brake is 24v and has a fine wire winding in it, it would have alot of inductance and assume thats why its a 60v fet, for spikes during switching.
My main concern is turn on/off voltage on the gate being an issue.
Any comments welcome.
( ps the electric brake had an issue and the clutch was stuck on, the electric brake gets hot now, and is probably related to why the fet got very hot ......no heatsink on it......., intend to remove electric brake and replace it with a resistor of similar value)

 

[fechter]

I wouldn't worry about the gate voltage. Most FETs can handle up to about 20v on the gate but typically run 10-12v.
The voltage spike from turning off the coil should be captured by a diode across the coil, so no worries there either.
You should have no problem replacing the stock FETs with something better.

 

[amberwolf]

( ps the electric brake had an issue and the clutch was stuck on, the electric brake gets hot now, and is probably related to why the fet got very hot ......no heatsink on it......., intend to remove electric brake and replace it with a resistor of similar value)

Most likely the FET failed; they usually fail stuck on, which would cause both those problems.

 

[whatever]

thanks so much for that, and taking time to read the post, have a fet on hand will pop in and fingers crossed.
thanks again

 

[whatever]

so I put in a z44n mosfet, its n-chanel, 55v I forget the amps but its plenty, is working fine, very small amount of warmth,
problem solved..........thanks guys for the advise