## Motor Slip

Consider a 4 pole induction motor with a line voltage frequency of 120 Hz. If the motor shaft spins at 2,000 rpm, what is its slip?

##
__
__**Hint**

**Hint**

The slip for an induction motor is:

$$$slip=\frac{(n_s-n)}{n_s}$$$

where
$$n$$
is the rotational speed.

##
__
__**Hint 2**

**Hint 2**

The synchronous speed for ac motors is:

$$$n_s=120*f/p$$$

where
$$f$$
is the line voltage frequency in Hz, and
$$p$$
is the number of poles.

The synchronous speed for ac motors is:

$$$n_s=120*f/p$$$

where
$$f$$
is the line voltage frequency in Hz, and
$$p$$
is the number of poles.

For a 4 pole motor operating on 120 Hz voltage:

$$$n_s=120*120/4=3,600\:rpm$$$

The slip for an induction motor is:

$$$slip=\frac{(n_s-n)}{n_s}$$$

where
$$n$$
is the rotational speed.

$$$slip=\frac{(3,600rpm-2,000rpm)}{3,600rpm}=\frac{1,600}{3,600}=0.44$$$

0.44