Technical terms

This chapter provides information on various technical terms and their meaning.

Standstill torque M₀ [Nm]

Torque, also referred to as starting torque, that the motor can generate at standstill. It can be maintained indefinitely at a speed n < 100 min^-1 and rated ambient conditions.

Rated torque M_n [Nm]

The torque that the motor delivers when it is operated at nominal speed and nominal current. Can be output in continuous operation S1 for an unlimited period of time.

Standstill current I_0rms [A]

Sinusoidal current RMS value. This is consumed at a speed of n < 100 min^-1 in order to generate the standstill torque.

Peak current/pulse current I_0max [A]

Sinusoidal peak current RMS value. Corresponds to approx. five times the standstill current and three times for AM806x, AM856x and AM807x. The configured peak current of the servo drive used must be less or equal.

Torque constant K_Trms [Nm/A]

Indication of the torque in Nm generated by the motor per ampere of standstill current. M₀ = I₀ x K_T applies

Voltage constant K_Erms [mVmin]

Indication of the induced motor EMF at 20 °C, based on 1000 rpm. This is specified as the sine RMS value between two terminals.

Rotor moment of inertia J [kgcm²]

Measure of the acceleration capacity of the motor. For example, at J₀ the acceleration time t_b from 0 to 3000 min-1 can be calculated based on the following formula:

with M₀ in Nm and J in kgcm²

Thermal time constant t_TH [min]

Specification of the heating time of the cold motor under load with I₀ until an overtemperature of 0.63 x 100 Kelvin is reached. This temperature rise happens in a much shorter time when the motor is loaded with the peak current.

Release delay time/application delay time of the brake t_BRH [ms]/t_BRL [ms]

Specification of the response times of the holding brake [+] when operated with the nominal voltage

Winding inductance L [mH]

Indication of the motor inductance. It is the average value for one motor revolution, with two energized phases, at 1 kHz. Saturation of the motor must be taken into account.