Quench heater discharge power supplies for the protection of LHC superconducting magnets.

1st Intervention	TE-MPE Piquet Team(16xxxx)
Responsibles:	Raul BIANCHI
	Yves THUREL
Developped	CERN TE-MPE
	2000-2002
Manufactured	Portugal
	EFFACEC
	Inde
	ECIL
Production	6500 Pc
Use
LHC
Fonction	Quench Heater
Power In	2 ~ 230V/-A
Power Out	+900V
Cooling type	Natural Air Cooled
Weight	25-35Kg
History:	Ludovic CHARNAY
	Frederic DALIGAULT

Simplified Schematic

Power Part simplified Architecture / Topology .vsd

Notes:

In the event of a magnet quenching, these power supplies will energise the heater strips inside the magnet. By this means the propagation of the quench is enhanced in order to prevent damage to the magnet coil. Each power supply contains a capacitor bank with 6 aluminium electrolytic capacitors (4.7 mF / 500 V). Two sets of 3 capacitors each are connected in series, resulting in a total capacitance of 7.05 mF / 1000 V. The nominal operating voltage of the capacitors will be Unom = 450 V giving a maximum stored energy of 2.9 kJ.

The warm and cold part of the heaters represent a 5..20 Ohms resistance, and the quench heater power supply can provide a 1 Ohms load minimum (destruction discharge above).

Manget types and their heater data: MBRC : 3.7 Ohms / 26.1ms, MQM : 14.6 Ohms / 102.9ms, MQY : 11.3 Ohms / 79.7ms.