Did I croak this coil?

[marko39]

I bought a new coil (helmet) for my yet to be started 39 engine. I had no power thru ignition circut so I ran a jumper wire from batt. to coil. Got engine running and ran for about 15 min. while I adj. carb. Next day installed spare resistor on coil and ran for 5 min. and coil died. Installed old coil and running again. Did I kill coil or should they be able to handle 6 volts while idling for 15 min. Got coil off eBay and it was from Carpenter and made in China. Mark