A single-bore 1 meter long 10 T Nb/sub 3/Sn dipole magnet with a 88 mm bore is being developed. Based on powder-in-tube (PIT) Nb/sub 3/Sn strands exhibiting 22 /spl mu/m thick filaments, a Rutherford-type cable with a stainless steel core of 25 micron is employed. All properties relevant for magnet design and operation like critical current, filament magnetization and coupling current control have been investigated experimentally. Their impact on magnet operation is discussed. The effectiveness and reliability of a quench protection system for Nb/sub 3/Sn accelerator magnets relies mainly on the normal zone propagation properties and properly designed and positioned protection heaters. We present measurements and calculations of propagation properties and discuss the consequences for protection heater design.