# Recognition of Acoustic Signals of Commutator Motors
## 3 Results of the Fault Detection of the Analysed Commutator Motors  
Measurements of the acoustic signals of the analysed commutator motors (the commutator motor of the electric impact drill and the commutator motor of the blender) were conducted in a workshop. The analysed devices were operational, except for the electric impact drill with a shifted brush (motor off). The author measured and analysed five states of the electric impact drill: healthy, with damaged gear train, with a faulty fan with 10 broken rotor blades, and with a shifted brush (motor off). Each electric impact drill had a commutator motor and had \(P_{EID}\) = 500 W, \(R_{EID}\) = 3000 rpm, \(V_{EID}\) = 230 V, \(f_{EID}\) = 50 Hz, and \(M_{EID}\) = 1.84 kg, where \(M_{EID}\)--weight of the electric impact drill, \(P_{EID}\)--rated power of the electric impact drill, \(R_{EID}\)--rotation speed of the electric impact drill, \(V_{EID}\)--supply voltage of the electric impact drill, and \(f_{EID}\)--current frequency of the electric impact drill. The author measured and analysed three states of the blender: healthy, with a faulty fan with two broken rotor blades, and with a faulty fan with 5 broken rotor blades. Each blender had a commutator motor and had \(P_{B}\) = 300 W, \(R_{B}\) = 10,000 rpm, \(V_{B}\) = 230 V,  
Figure 26: SVM model (for the example two features of X and Y). and \(f_{B}\) = 50 Hz, \(M_{B}\) = 1.75 kg, where \(M_{B}\)--weight of the blender, \(P_{B}\)--rated power of the blender, \(R_{B}\)--rotation speed of the blender, \(V_{B}\)--supply voltage of the blender, and \(f_{B}\)--current frequency of the blender. To compute patterns, 20 one-second training samples of the electric impact drill and 18 one-second training samples of the blender were analysed. To analyse the proposed approach (please see Section 2), 125 one-second test samples of the electric impact drill and 102 one-second test samples of the blender were analysed. Acoustic data of the analysed commutator motors were evaluated by Equation (3). It defined the efficiency of recognition of the electric impact drill/blender (\(E_{EID}\)):  
\[E_{EID}=(N_{EID})/(N_{AEID})\times 100\% \tag{3}\]  
where \(E_{EID}\)--the efficiency of recognition of the electric impact drill/blender for the selected type of acoustic signal, \(N_{EID}\)--the number of test samples of the electric impact drill/blender tested properly for the selected type of acoustic signal, and \(N_{AEID}\)--the number of all test samples of the electric impact drill/blender for the selected type of acoustic signal. The total efficiency of recognition of the electric impact drill (\(TE_{EID}\)) was used to evaluate the \(E_{EID}\) of all analysed acoustic signals of the electric impact drill. \(TE_{EID}\) was expressed as Equation (4):  
\[TE_{EID}=(E_{EID1}+E_{EID2}+E_{EID3}+E_{EID4}+E_{EID5})/5 \tag{4}\]  
where \(TE_{EID}\)--the total efficiency of recognition of the electric impact drill for the five selected types of acoustic signals, \(E_{EID1}\)--the efficiency of recognition of the healthy electric impact drill, \(E_{EID2}\)--the efficiency of recognition of the electric impact drill with a damaged gear train, \(E_{EID3}\)--the efficiency of recognition of the electric impact drill with a faulty fan (five broken rotor blades), \(E_{EID4}\)--the efficiency of recognition of the electric impact drill with a faulty fan (10 broken rotor blades), and \(E_{EID5}\)--the efficiency of recognition of the electric impact drill with a shifted brush (motor off). The total efficiency of recognition of the blender (\(TE_{B}\)) was expressed as Equation (5):  
\[TE_{B}=(E_{EID-B1}+E_{EID-B2}+E_{EID-B3})/3 \tag{5}\]  
where \(TE_{B}\)--the total efficiency of recognition of the blender for three selected types of acoustic signals, \(E_{EID-B1}\)--the efficiency of recognition of the healthy blender, \(E_{EID-B2}\)--the efficiency of recognition of the blender with a faulty fan (two broken rotor blades), \(E_{EID-B3}\)--the efficiency of recognition of the blender with a faulty fan (five broken rotor blades).