Scheppach Spare Motor £374 and two months to deliver!

[GPB]

I had a Scheppach table saw motor re-wound at Carwood (Rewind) in Yeovil. Only took a few days and cost around £200.

Saw has been problem free ever since, however it is run off a 16 amp supply.

 

[deema]

The is 2.4KW with a power factor of 0.98 making it c2.5KVA. The Full Load Current (FLC) is stated as 10A but is actually slightly higher at 10.4A. Inrush current, which is the current that is pulled by the motor at start up isn’t stated, but is usually circa 6 times the FLC which means that the motor is pulling around 62A when starting up. The motor at standstill is seen electrical as a complete short circuit. It is only as the motor is turning that the magnetic inductance creates impedance to reduce the current. The faster the motor turns the more inductance is created the lower the current. This is the reason that say 4 pole motors (c1400rpm) have a higher FLC than an equivalent 2 pole (2800RPM) Motor.

You may have had an unusually slow burn 13A fuse in your plug which is why it worked originally. BS1362 13A Fuse is required to operate at 1.9 times rated current (24.7 A) within 30 minutes, and also that the fuse shall have a non-fusing current of 1.6 times rated current (20.8 A). The higher the current the faster it will blow. The allowed tolerance means that at around 60A compliant fuses will blow any where between circa 0.4 and 5 seconds at this current load) However, the motor you have should blow a standard 13A glass fuse every time you start it up if you have one at the bottom tolerance and infrequently at the top. To run the motor successfully every time You need a dedicated 16A supply straight from your consumer unit with a 16A class C MCB that is protected by a RCD. (Or an RCBO if there isn’t a RCD)

The fact that the motor starts with no load is a very good indicator that the capacitors and windings are OK. However a cheap multimeter can be bought to check the windings and capacitors for absolute certainty.

 

[weekend_woodworker]

Thanks for all the replies. Looks like I need to ask for a 16amp supply from Santa! The only thing putting me off at the moment is that I don’t have any spare spaces in my fuse box for another MCB. Time for a bit of head scratching.

 

[dzj]

Maybe new bearings might reduce inrush current enough to make your problem go away.

 

[Doug71]

If you really wanted to be a dangerous cheapskate you could always put a nail or a plug of copper in place of a fuse to see if it works. Although I would never do it myself. Won't cause any damage to the machine as the fusebox would trip first before anything like that happens.

Another dangerous cheapskate method I have seen is to put a piece of 15amp fuse wire alongside the blown fuse in the 13 amp plug.......

 

[weekend_woodworker]

With a view to getting a 16amp power supply I reassembled the machine yesterday. I found that if I did not put too much tension on the drive belt it will run off 13 Amps . I think I still ought to get a 16amp supply put in, but it is great to have it up and running again rather than in pieces blocking up the garage.