I found this at
adoremus.org/0305SantusBells.html. Your answer is at the end but the rest gives a great explanation of when the bells can be rung. It’s short.
Nearly 350 years after the introduction of the Sanctus bells rung during the Liturgy, the Council of Trent (1545-1563) formally mandated their use during the celebration of the Mass. Thus for the first time the use of the bells became a required part of the official rubrics of the Mass. Ringing the bells is still required for the “Tridentine” Mass; though the practice was made optional when the post-Conciliar Missal was promulgated by Pope Paul VI in 1969.
Ringing the Sanctus Bells
Sanctus bells are traditionally kept on the epistle (left) side of the credence table during the Mass, and ringing them has long been the responsibility of the instituted acolyte or altar server.
The bells are rung at three or four points during the celebration of the Mass:
- Sanctus bells are first rung prior to the consecration at the epiclesis when the priest prays to the Holy Spirit to change the gifts of bread and wine into the Body, Blood, Soul and Divinity of Jesus Christ.
- The bells are rung a second time as the priest elevates and presents the Body of Christ.
- The bells are rung a third time as the celebrant elevates and presents the chalice filled with the Precious Blood.
- The bells may be rung a fourth time as the priest-celebrant consumes the Precious Blood. This custom, which originated from the rubrics of the Tridentine Mass, may be continued since it is not forbidden nor suppressed in the latest version of the General Instruction of the Roman Missal.
In some cases the bells are rung for three short bursts at both of the elevations/presentations as defined by the rubrics in the 1962 Missale Romanum. These three short bursts are said to represent the three persons of the Holy Trinity. If executed well this triple ringing can sound quite solemn, but a single ringing of the bells at each specified point in the Mass is adequate.